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Credit: Alan P. Santos
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Interview of Elaine Oran by David Zierler on June 18, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
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Interview with Elaine Oran, Professor of Aerospace Engineering and O’Donnell Foundation Chair at Texas A&M. Oran describes her core interest in fluid dynamics and why aerospace engineering provides an ideal home department for her research. She recounts her childhood in Philadelphia, her early interests in science, and her undergraduate experience at Bryn Mawr. She explains her decision to attend Yale for her graduate work in physics, where she focused on phase transitions, and she explains the opportunities that led to her work at the Naval Research Laboratory. Oran describes her research in laser-matter interactions and the value of the Laboratory for Computational Physics. She discusses her early interests in reactive flows and how this field became broadly applicable across the sciences. Oran describes being in Washington on 9/11 and her involvement in studying the explosions. She discusses her decision to join the faculty at the University of Maryland and her research in fire whirls and she explains her subsequent move to A&M where she was attracted by the interdisciplinary research opportunities. Oran describes her work in numerical simulations and the interplay between theory and experiment in her research. At the end of the interview, Oran emphasizes the importance of spontaneity and an openness to pursue science in unexpected directions.
Okay, this is David Zierler, Oral Historian for the American Institute of Physics. It is June 18, 2021. I am delighted to be here with Professor Elaine Oran. Elaine, it's great to see you. Thank you so much for joining me.
My pleasure, David. I think this should be a very interesting experience, hopefully for both of us.
Absolutely. To start, would you tell me please your current title and institutional affiliation?
Currently, my main affiliation is Professor of Aerospace Engineering, the O'Donnell Foundation Chair at Texas A&M University.
When did you get to Texas A&M? It's pretty recent.
Yes, I just started there a couple of years ago. Less than a year before COVID hit us.
Tell me about the O'Donnell Chair. Who is or was O'Donnell?
The O’Donnell Foundation is a charitable and educational foundation that has put considerable funds into STEM education. Well, this is embarrassing. O'Donnell is apparently a great philanthropist who's given a lot into to the Texas educational system. There are a number of O'Donnell chairs at TAMU.
I'm curious why aerospace engineering and what that might suggest more broadly about your research agenda at this stage in your career.
Well, how this happened is a part of my history, and connect to past events. The work that I do is extremely multidisciplinary. It’s curious, but when I went to the University of Maryland, for example, people would ask me, "Well, which department are you going to? Physics? Something else? What are you going into?" I think could easily have gone into physics, physical chemistry, chemical engineering, mechanical engineering, computer science, really almost any engineering field almost. One equally as well as the other. So, the question is, why aerospace?
When I was working at NRL, aerospace had a very large presence in fluid dynamics. If you were going to show your work in almost any area of fluid dynamics, you would go to the general Aerospace meetings. The American Physical Society, at that time, was much more limited. They didn't to think fluids were anything except subsonic turbulence, so only a very narrow range of topics was appreciated. In fact, they kept saying fluid dynamics was dead and used up. It's not like now, when we understand that fluid dynamics gives us a deep and broad basis for so many different fields. Almost everything you is a fluid. At that time, physics had a very limited picture of the role of fluid dynamics in physics, and even of what physics is.
I don't know how these thoughts all evolved. I guess I could dig it up historically from my memory or looking at records of meetings and publications. It’s a historical deviation, which is probably worth study in itself. I was working particularly in high-speed fluid dynamics. Actually, two types, first shocks and blasts, and then in reacting flows. Reacting flows are flows with a localized energy release in them, so they're very dynamic and transient.
And I was also doing research in atmospheric chemistry and physics, which led me naturally into fluid dynamics. Because, as you notice, the earth has a moving atmosphere. The aerospace community (through the AIAA) was very welcoming, much more so than the existing fluids community, based in APS fluids. I was encouraged by AIAA, they were inviting into their meetings, publications, and structure, I paid as much attention to them as I did to APS, and I liked the way they were going. I became very involved with them and took on and identity as a physicist working in aerospace engineering, and then as an aerospace engineer.
I'm curious about your additional affiliation with the Mary Kay O'Connor Process Safety Center. What is that, and how does it align with the research that you're doing?
Actually, I have several affiliations. They seem to be changing every day, and once I have one, it just doesn’t go away! They just append (laughter). Such as University of Maryland, University of Michigan, Leeds University, the Naval Research Laboratory- they just accumulate. And there are affiliations within affiliations.
The Mary Kay O'Connor Process Safety Center is a very interesting organization. I did not really know much about it before I came to TAMU, but I had heard of industrial process safety though colleagues in Europe. It’s a very important field, the industrial side that makes sure that industry follows safety practices and considers safety. There are journals devoted to this, meetings and workshops devoted to different aspects of safety in different industries. I didn’t see much in the United States, but I knew there were programs in Europe and even degrees given in industrial processing safety. TAMU has this Center, which is a substantial effort that brings together the industrial community and academia and makes everyone award of important safety issues. And it trains students.
In the petroleum and chemical processing industries there are many dangers and more-than-occasional explosions in storage facilities and processing plants. The Center is a place where people can go and learn what the newest techniques or safety considerations, meet their colleagues, and so forth. In some ways, it plays the role of a professional society in that it provides a center for people to come. But it also teaches students. And they have a journal. I am not as active in the area as I would like to be, there are too many time constraints, but my work certainly relates to that field.
This is probably not going to be an easy answer, but just as a snapshot in time circa June 2021, what are you working on these days?
Oh my gosh.
I knew it (laughter).
It's like, "What's new?" Don't you just love that question? (laughter). Well, I have a spiel, and I could bring it up for you with a list of current projects. I don't know if you want me to do that or not.
What's most interesting to you right now? Of all the things that you are working on, what's really exciting?
Well, pretty much everything. That's part of my problem. I'd say the most compelling at the moment, is trying to organize the design and building of a very large experimental facility at TAMU, which we now call the Detonation Tube Research Facility. It's based around a large experimental apparatus, actually a giant tube, which is going to be 200 meters long and two meters in diameter. We're going to use it to study specific kinds of high speed chemically reacting flows on a slightly larger scale than they have been studied before. Usually, these studies of these flows are done in small tubes in laboratories, or they're done crudely out of doors or just for the purpose of getting a number out. We want to look at the structure of the propagating waves, and we're going to be subjecting the flows in this tube to the very latest in experimental diagnostics, optical and otherwise, that are now under development or exist at TAMU.
So first, I'm going to pull together the expertise of some very prominent people here to try to figure out what's going at the front of some of these propagating chemically reacting waves. We're going to look in at those waves and the structure of them in as much detail as we can. One of the things I learned about ten years ago was that you not only learn from going smaller than usual, down to micro and nano, which are critical sizes, but you also learn a by going a little bit larger than whatever is normal. Maybe as big as the universe, for example (laughter). The physics often changes, different things become important, and sometimes you can spread things out and see more, in some sense. The idea is that we're moving to the next largest stage with this experimental apparatus. And it's the possibility of building this facility that brought me to TAMU.
Tell me about the facility. What's so unique about it for your research?
It will be the largest research shock-detonation tube, certainly in the country, maybe in the world. There are some larger facilities, but none devoted to looking at the structures of very fast, high-pressure waves that interest me. Now, this is a very interesting problem. One type of very high-pressure wave, for example, a detonation, which is a very fast chemically reactive wave propagating through an explosive mixture at Mach two to five, has a distinctive structure. It's not just a flat front. There is a very complex structure behind it. And in that structure, there's another structure, a region in which reactions, chemical, or in the case of supernovae, nuclear reactions, are occurring very quickly. And in reactive regimes for which we do not have any reaction model at the moment.
This facility will give us a chance to look in in a more detailed way at some basic properties of these waves. Here is the question: "Can we go in o this wave to study something at the front which is at twenty or fifty atmospheres and moving at Mach four?" (laughter) This has a number of interesting challenges, but it also has some interesting practical applications. The kind information that we might be able to get from this goes from very basic ideas, which could sound like getting knowledge for knowledge's sake, but it's not quite that because it will also give information that could immediately go into applications. These applications go anywhere from aspects of industrial processing which prescribed regulations for plants and other things, to control of accidental vapor cloud explosions, to military devices.
We’re looking for what is actually happening in and so driving these reaction waves. And that I find very exciting. I like the kind of work that goes from something very basic, which will explain something no one could understand before to just something that is just for use immediately. That’s one of the exciting things I’m doing. Do you want to hear seven or eight more? (laughter).
I wanted to hear the first one you wanted to talk about. That's the idea.
Okay, now the reason I chose that is because I'm currently trying to deal with a design meeting related to this now.
In what ways is A&M really a great place to do this, given its emphasis on interdisciplinary science, breaking down those barriers between the departments?
How did you know about that?
Oh, because of so many people I've interviewed at A&M. I've heard this.
Who have you interviewed?
I'm thinking of Marlan Scully, right off the top.
Well, he's right on that. TAMU is wonderful for me because I am a multidisciplinary person. I don't know what I'm going to do next, and to me, it really doesn't matter as long as it’s interesting and fun. I noticed that when I arrived at TAMU, I was encouraged to talk to people from other departments. So, I just did. Some interdisciplinary work was encouraged at Maryland, but when you went from science to engineering, uh-oh. That wasn't as well-respected. It doesn't matter at TAMU. You can talk to anyone you want, and everybody's been terrific about sparing time for me. It has a good feel to it, as it feels as though you really can do a little exploration.
You can have your best colleague be in English literature, for example (laughter). Or anthropology, or the study of women Indian chiefs, or something really different from what you're doing. And it's comfortable to do that. The interactions are comfortable and encouraged by the university.
Regardless of current affiliations and the HR component of that, is it useful for you to think of having really a home discipline or a home department? Or really, a branch of science that is your wheelhouse and that you use to expand into wherever you want to go, albeit physics, engineering, or even computer science? Do you think in those terms at all?
Well, I was encouraged to think in terms of aerospace, but aerospace is really not a field. Aerospace consists of many disciplines, which was very lucky for me. And as I said, the community was really encouraging to me in aerospace. I think in general that engineering is better than science for being able to go any direction you want, into the sciences or into engineering. As far as a home discipline, I'd say it’s aerospace, or physics, or fluid dynamics, or computers. It's a little bit hard. It depends where the current emphasis is. If I say aerospace, it's broad enough to cover everything.
I wonder how the kinds of collaborators that you work with might illuminate that answer. In other words, if there are collaborators who represent areas of expertise that are complementary to what you bring to the research.
That would be a lot of experimental work, for example. The people in optical diagnostics, for example, would say, "Oh, she's an expert in combustion, chemically reacting flows." People in computers would say, "Oh, yes, didn't she play with some of the very early connection machines?" (laughter) So I'm not sure how other people view anything I do, actually. It usually surprises me.
A current question, how has your science been affected by the pandemic one way or the other, and now that we're starting to peek back toward normal life, what are you most looking forward to getting back to?
During the pandemic, I focused primarily on computational work, simulations, and my students focused on those, too, and we produced quite a lot of research and papers. I don't think I've ever written so many papers in my life (laughter). Or edited so many papers as during the pandemic.
It's about all you can do, write.
We tried to do some experimental work. It wasn't really safe. I learned a lot. I learned that I really enjoy being isolated, sitting and working near at a beautiful little lake, editing and writing papers, playing on the web. I think I did not mind the pandemic, personally. My students and colleagues, however, had a terrible time. The group meetings on Zoom are more important than ever to keep them connected. The first thing I wanted to do was find out who was going crazy. And I’ve borderline cases during some of those zoom meetings.
But as far as students are concerned, I threatened them and told them if they're telling me they're not feeling well, I'm calling the police right away. That would make everyone laugh. We'd be okay for the rest of the hour because no one believed I would really take any drastic action. I think we're coming out of the pandemic now, and I'm seeing that faculty, students, and friends are having issues coming out. I didn't expect that. Actually, I didn't know what to expect. But I didn't expect some of the reactions that I've seen.
It's a difficult transition. We've been in this for a long time now.
Right. We're very comfortable in it. I used to travel two or three times a month. I would go to China and come back in a few days. I haven't traveled at all.
So, in the world of experimentation, as it's starting to become safe again, what are you most looking forward to getting back into?
I want to get this detonation tube built.
What's it going to take?
Coordination between the companies the university has hired as a design/build team. I don't know them, but they have a good reputation. Between them and my scientific team and the cooperation of the university facilitators. It’s a management project.
I'm curious sort of looking forward, given your interests and contributions in the field of computational analysis, is quantum computing exciting for you? Even if we're not sure of what it might be good for, do you have an intuitive sense that this is really going to allow things that aren't currently possible?
Yes, I do. I think it could say something here. I'm not convinced that quantum computing will give us what we need for computing chemically reacting flow, but I think it night it might give us part of it. I've been asked this by a number of people, and I did spend quite a bit of time looking into some of the details and issues involved. I'm certainly not going to rely on it for great improvements in practical computing in the near future. And if I didn't have so much else going on, I might be working on the problems, which are really counterintuitive. A physicist has to learn a whole new set of intuitions once something like entanglement come in, not knowing for certain if you're here or there, etc. Entanglement has always fascinated me.
This question inevitably has philosophical connotations to it, but given your interest in the simulation of physical systems, do you think that if quantum computing allows us to simulate experiments for which there's no hope of doing it in the real world, like building a high enough energy accelerator to find out if supersymmetry is there, in your lifetime, and maybe anyone's lifetime, we're probably not going to build that machine, but if we have quantum computers that can simulate operating at those energies, scientifically, will quantum computers allow us to redefine deductive logic in science?
Not deductive. Look, computers only can compute what you tell them to compute. If you miss a process, like if I forget to put radiation transport into my code, and that's the controlling process, my code isn't going to tell me, "Elaine, you forgot radiation transport." But my code is going to tell me I have the wrong answer, not why.
So, I guess the question really is, whatever quantum computing is going to do that classical computing does not, does not include what you're saying now?
I am pretty sure it does not. Because it's not going to think for you. It'll only tell you faster whether you're right or wrong. As someone once said to me, "If I had a perfect simulation of something, what would be the difference between the real thing and that thing?" Well, of course, nothing (laughter). But think of what we would need to have that perfect simulation. We'd need to be able to put the model together. Computers can only solve models or algorithms. Now, maybe they can make models, too, if you teach this computer to learn, and you combine that with reality. It can tell you that something is missing. But it won't tell you what's missing. It could, however, give you a set of rules to follow, which is a model in some sense. So, we won't learn what physics is important in problem, but we could learn how to account for what is missing. We won't learn about the physics but knowing that something is missing could allow us to formulate new models. And that’s useful.
Well, this has been a very current and forward-looking conversation up to now. Let's engage in some history. Let's go back all the way to the beginning and start, first, with your parents. Tell me about them.
Well, there are lots of ways to talk about your parents. My mother was born in Baltimore. Her mother was born in Baltimore County on a farm that my great grandfather started when he came to this country in the 1800s, I believe, from somewhere in Europe. My mother grew up in Baltimore, but she ran away when she was sixteen. She was the second of seven or eight children and tired of childcare. She went to Philadelphia on her own, somehow managed to put herself through some kind of an educational process and got a couple of degrees. She studied anesthesia and became an RN because women didn't become medical doctors. They were actually looked down on if they became a doctor.
So, she became a nurse, and then she became an anesthetist. And she was a very, very independent person who supported herself. I think she was a “flapper.” I saw pictures of her all dressed up in outfits at parties. And I think she had a fairly good life that she created all by herself. I don't know too much about her childhood. I do have some pictures of her as a child. She died when I was eighteen, so I missed a lot of opportunities to find out things, although there was some family gossip that I just vaguely remember. I do know she was good in math because I remember her teaching me something very interesting. When I first learned how to take a square root, that was in elementary school, she taught me how to take a cube root. Now I don't know how to take a cube root, I can't remember (laughter).
But she was good in math, she had some musical talents, and she did very well in exams. She was a very smart lady. When she got married, she wasn't allowed to do anything but be a housewife and give anesthesia in my father's dental office. My father was born- I guess south of Kiev. He once tried to show me on a map, but I'm not sure I remember where that was. He had a very rough time as a child. No money. No food. They foraged. My grandfather went to the United States before World War I, my grandmother and the children didn't make it over until after World War I. So, there was a separation there. And then, they were able to hook up again by accident.
Is your sense that it was more of a push or a pull to come to the United States from Ukraine? Was there anything that they were escaping? Or was it just better opportunity in the United States?
The conditions in Europe were horrible. It had been really rough. Villages were burned down, people were treated badly. One wave of Army came in, then another wave, the Germans, the Russians, then the Germans and Russians again. There was no living. The stories were right out of a book.
And where did your parents meet?
They met in Philadelphia, where my mother was working at the hospital, and my father had a dental office nearby. And she was asked by a friend to go around and collect rents from property where my father rented office space. She was the rent collector.
And where was the family when you entered the scene?
Well, when I entered the scene, my father had gotten back from World War II, and he was in and out of a hospital in Georgia.
Where did he serve during the war?
That's a good question. I know he spent quite a bit of time in the Pacific. I know he was in Port Moresby. There are very bad stories about his experiences there. I think he was shot there.
And it sounds like maybe it was difficult getting him to talk about his time during the war.
Yes, it was. He talked a little bit about it just before he died. And that was amazing to hear. I really don't know how much of what he said was true because I know he liked history. But I know about the bullet wound. And I also know that he was around the Pacific. I also know that he had contact with German soldiers, probably in the United States after the war, before he left the military. At one point, as a child, I remember him talking about interviewing German soldiers, which he could do because he spoke a lot of languages. I think he spoke a number of Slavic languages, he picked up Italian in South Philadelphia, he could mishmash everything together. He could sing the Ukrainian national anthem.
Did he benefit from the GI bill? Was that helpful for his professional studies?
No, he had already finished school before the war. He was a dentist when he went into the military. He went into the medical corps, but in the Pacific, he was doing all kinds of medicine and surgery, anything that had to get done. He loved surgery. Cut and pasting (laughter).
How long were you in Georgia? Do you have any memories from then?
No. Apparently it was one year.
And then, it was back to Philadelphia. And where do you grow up? What town did you grow up in?
Where in South Philadelphia?
Fifth and Wharton. Did you grow up in Philadelphia?
I'm not from Philadelphia, but I was at Temple University for a time.
Our house was on Annin Street, which was two blocks below Washington between seventh and eighth. Right by the Italian Market.
I used to go to the Market with my mother when I was a child. I once bought a chicken and carried it home in a bag like this. It was terrific. I went to George Washington Elementary School there on Washington Avenue.
Was it mostly an Italian neighborhood where you were? Mixed?
No, it was a block of Italians, a block of Irish, a block of Polish, a block of Jews, a block of this, a block of that. It was a very mixed and interesting neighborhood. And we were there until I was about in fifth grade.
And you went to public school there?
And then, where'd you go after fifth grade?
Well, we moved to the northeast part of Philadelphia. I went to Northeast High School.
The Great Northeast.
Nothing great about it (laughter). Yes, the Great Northeast. And then, from there, my father moved to Cheltenham.
When did you start to get interested in science, yourself? Maybe even before formal education.
I think I was always interested in science, and it probably because of science fiction. The earliest show I remember on television was Tales of Tomorrow. A very early television show (laughter).
Futurism kind of stuff?
Futurism and maybe not so future but happens from the moon or the planets. I was actually very confused as a child. I did not know what was real and what wasn't. I didn't know, for example, that we weren't riding around the universe in spaceships with laser guns until I was at least nine years old.
Did your high school have a strong math and science curriculum?
High school, I barely remember it. It was OK. I got most of it from external courses. There were courses you could sign up for, given on television, where you took math courses and extra science. Pretty much, I just muddled through high school, just waiting to get out. [laugh]
Between your grades, financial considerations, and geographical considerations, what kind of schools did you apply to for graduate?
Women's colleges, specifically.
What was your motivation there?
A good education.
Is that about going into science, but not wanting to be held back as a woman? Was that part of it?
No, I wasn't that sophisticated. No, I was only a very naïve sixteen. The only thing I knew is that I wanted to get out of high school.
But when you say good education, why not Harvard or Princeton?
Well, first of all, women were not admitted to Harvard or Princeton then. You could go to Radcliffe. You couldn't go to Princeton. You could go to Pembroke. Not Brown. Everyone from high school was going to the University of Pennsylvania, so I wasn't going to Pennsylvania (laughter). I applied to women's colleges, which just seemed a good idea. I thought you could study there with less interruption, you would be less bothered, wouldn't have to get involved in all sorts of social issues, for which I was totally unprepared and inadequate.
So why Bryn Mawr?
By accident. It turns out, believe it or not, it's a family school for me. There are quite a few relatives of my mother’s who went there. Why Bryn Mawr? It was close enough to home and far enough from home. I couldn't live at home. I had to live there. I could get home because my mother was sick and soon to die, and I wouldn’t be that far away. I went there because I went for an interview for Wellesley, and the woman who picked me up at the Main Line railway station took me to see Bryn Mawr, and then she interviewed me for Wellesley. It turned out that I had a cousin named Elaine who went to Bryn Mawr, and I thought that was and interesting coincidence, too. As it turned out, I had several cousins who went there. They were from the wealthy side of my mother's family, not her side.
Was the game plan to pursue science from the beginning? Or you were open-ended in that regard?
I had no idea what I was capable of. Absolutely none at all. Most people have a direction. I just wanted to see what I could do. I had no idea, no preconceptions, no plan for the future. I couldn't imagine, at age sixteen, living over twenty. This is a different point of view than most people have, I know that now. But that's what was driving me. I had no idea I could even get through college, or where the money would come from. I had a year's credit in chemistry from a summer program at Cornell University.
So, I came with advanced placement in chemistry, advanced German, and perhaps some other advanced credit. I thought "Okay, I'll major in chemistry, get out in three years, save some money, and I can get on with my life." It didn't work that way. I discovered physics my junior year and added another major. But earlier I didn't know what I was going to major in. The night before I had to choose my major, I dreamed I went to the Chemistry Department, they rejected me. Then I went to the German Department, and they said, "That's fine. You can be a German major." My father would've just loved that.
But I was thinking about linguistics for a long time. I liked languages, the structure of language. And I think structure of language was just coming into its own at that point. Chemistry did accept me, but I was not the best chemistry major; I wound up double majoring, chemistry and physics. I had a knack for physics that was really surprising. I didn't know it until I took my second semester of physics. I could just do everything. And I don't know why. I still don't know why I could do all the problems.
Were there any professors who you considered mentors or were really formative in your development as an undergraduate?
Yeah, there were several. My German professor, Herr Schmidt, he was good. The romantic writers, I loved them. Scientifically, there was a professor, Jay Anderson, who taught chemistry but also computing. I learned how to program Fortran in 1962 or '63. That was amazing because, if I think back, this computing start gave me a real edge on everything. There was a physics professor, John Pruett, who was very encouraging. And then, there was this famous professor at the college, Walter Michaels, who used to ”tell it like it was,” tell us where we would go to graduate school and be able to find a hospitable environment, where we should never go because we'd never finish. No student of his had ever been able to graduate from some programs, no matter how good she was. There was a lot of issues about women in science.
Did you have a sense as an undergraduate that there was a world of theory and a world of experimentation in science?
Yes, I understood that there was a difference between theory and experiment.
Did you gravitate toward one or the other?
Girls in general did not get the practical kinds of background that prepare you for experimental work. They didn’t go into garages and play with engines, and they weren’t given trains to play with. My physics professor essentially had to give all of us a remedial course in being in a laboratory. We had to be taught, essentially, how to hold a hammer. There weren't that many of us in physics, so we each were given a lot of attention. It was much easier for us to become theoreticians. And the computers were right there and didn't involve those certain skills that boys seemed to have naturally. I really did enjoy the laboratory experiences.
Do you have a specific memory of when you realized that you would pursue science for graduate school or even think of science as a career path?
Well, pursue it for graduate school, yes. That's when I was in college, and they asked me what I wanted to do afterwards, and then they suggested graduate school. So I started applying to graduate schools. I also had a backup, and that was with working for a woman at Bell Labs, who had been at Bryn Mawr. She was, I think, a geology major, but she was a then crystallographer and offered me a very nice job when I finished college. I considered that my backup if I didn't get into graduate school.
What kind of advice did you get about programs to apply to, and did you have any concerns about jumping into a coed environment?
Oh, no, no, no. The courses were co-ed at Bryn Mawr. We had students from Haverford. Bryn Mawr had a graduate program in physics, chemistry, sciences. So, it was a coed class environment almost from sophomore year. No problem with that at all.
So, what kind of advice did you get about programs to apply to?
Well, there were certain places not to go to because they're not very hospitable to women. And then places to apply, where they were hospitable. I went to a place that was on nobody's list, which was an interesting experience. Dr. Michaels was pretty good at telling us where not to go, as far as his knowledge went.
So why Yale?
Well, I went to Yale because my husband got into law school there, and we decided that that was probably one of the few law schools in the country from which he could graduate, given his biases and his leanings politically and in terms of things he liked to do.
Coming to Yale in the late 1960s, I'm curious, were you politically active at all? Were you involved in any of the protest movements that were going on at that point?
That’s a very interesting question. I was a science nerd. My husband was very active in socially and politically. I followed along. When the Grateful Dead came to cause a riot and have fun, and set up a big happening, I went, but I didn't organize it. I was busy studying my science. I remember that we were quite scared a couple of times, and there was one point, when residents just evacuated New Haven.
Did you only apply to physics graduate programs? Or you were open to other areas to pursue?
No, no, just physics.
So why did physics win out over chemistry?
Well, I was better at physics. I liked it more. I could do the problems. I don't know why I could do the problems, but I could. It was a talent that I didn't know I had. I had no idea I had that talent until second semester of physics. And then, I just went with it because it seemed to me I not only could do it, but I liked it.
What kind of physics did you want to pursue at Yale? What were interesting and exciting at that time?
I started off thinking, "I should go into elementary particle physics." That didn't last too long. I don't really remember it all too well, to be honest, just that I didn't really know what I wanted to do because I didn't really know how to separate one field from another. I knew there was nuclear physics because my friends took those courses, and I heard what happened in them. I liked solid state physics. I liked statistical mechanics a lot, and computers had not really been applied much at that time to stat mech. There was a huge opportunity to do something on the cutting edge and not even know you were doing it. Anything you did was different.
As a woman navigating the department, were there any difficult periods? Or you found it to be an easy transition?
It was a nightmare. I had never seen such an unsupportive, hostile environment. I didn't expect it.
You mean specifically for women? Or just for grad students in general?
I never really figured that out. But certainly, more so for women. For me. You always think, "Well, maybe it's just me." (laughter) But I was not used to that after being intellectually coddled at Bryn Mawr, where were getting a lot of attention and being whipped into shape mentally. Nobody cared at all or paid any attention in graduate school. It was extremely hostile and biased against you I think I learned all my physics as an undergraduate.
Were there any women faculty? I know, obviously, nobody was tenured until Meg Urry. There were no women on the faculty?
No. I was also in Engineering and Applied Sciences after a couple years. because stat mech and solid state were primarily in that department. So, I spent the first part of graduate school in physics, and the second part in applied sciences. There were no women faculty at all, that I recall. There was one instance of a women whose husband had a position, and she was given a research position and treated quite badly. Everything you hear that can be not good was pretty much true. It was a hostile environment.
Who was your graduate advisor? And was that decision a way to counteract some of the hostility?
Who were some of your supporters?
The one person I remember as being a supporter was Richard Chang, who was the advisor of a friend of mine, Joan Lewis, and he was a very kind person. His fields were optic, laser spectroscopy, and solid-state physics. He's the only one I remember as being supportive. There was one professor, also, who was the nicest person to me in physics. And he was the nicest person because one day I passed him in the hallway, and he actually looked at me and said, "Hello, Elaine." (laughter) That was Glen Repka.
Didn't take much, huh?
What was the intellectual process for developing your thesis research?
Go off alone, come up with an idea, and write a thesis.
What was the idea, and how did you come to it?
The idea was based on statistical mechanics. It was looking at a complicated Hamiltonians for spin-1 problems. How did I come up with it? It was related to statistical mechanics, and I could see a lot of ways of solving it at various levels with the computer. So, I solved it many ways, from the most elementary to the most complex way that I could do at that time with the computer. And the computer was something you had to crank it by hand almost. I didn't have access to computers that were as good as I had at Bryn Mawr! But I went off and used the computer skills I learned at Bryn Mawr to develop a program to solve this problem at various different levels of complexity. And now, I can barely remember what it is, to be honest. I think I have the thesis somewhere. Someone (David Landau) once told me he had the thesis on himself. I couldn't believe it. But it's certainly not anything I would even look at twice now.
Looking back, do you have a stronger sense that there were advances in computation that allowed you to conduct this work? Or do you have a stronger sense that there were limitations in what computers were able to do, and that, in turn, limited what your research was able to do?
The research was limited by computing availability. I was using what I had to the hilt. I had to essentially make it all up.
You were writing programs.
Oh, yes. You wrote the equations, you wrote the programs, you tried to find ways of solving these interaction problems. If I'd have had the kinds of computers and algorithms I have now, I'd have done the kinds of work people are doing now. Large Monte Carlo, or large multi-billion particle simulations. Back then, you just solved models at higher and higher levels and looked at the new physics at each level of solution.
What were the central conclusions of your thesis?
Oh, I remember it had to do with the phase transitions and how the order changed when you got the more complex solution. Something like that.
Were you following what Ken Wilson was doing at Cornell?
No, I’d never heard of him back then. I was- following my nose.
You were operating in your own phase transition world.
Right. As usual, in my own world. Nobody cared, there was nowhere to go, nothing to present. Just my own world.
For better or worse, anything memorable from the oral defense?
I got through it. That was the main thing. It's interesting you would ask that (laughter). The main thing is, I got through it. I don't believe anybody at Yale, except perhaps Richard Chang, ever thought I would.
Because it can be very pro forma, you can take a beating, or you're the world's expert, and the professors want to learn from what you found.
I don't think they cared about what I found. But there was one professor who wasn't so bad. Ira Bernstein. But the others, they couldn't care less.
This is not a very flattering portrait of Yale that I'm hearing.
No, it's not a very flattering portrait of Yale, but it was Yale at that time. Now, I think it's a very different place. And it started to be a different place as soon as they admitted undergraduate women and realized they had to get their act together. Then, there was nothing that I could do except try to get out.
What was the timing with your husband and the law program? What was the two-body challenge at that point?
He started at the law school the same year I started in physics. He finished in '69. I was still going trying to find a topic. He got a Reginald Heber Smith Fellowship to work in legal services in Connecticut for a couple of years. And then, just before I finished, we both left New Haven. I finished the thesis while we stayed with friends in Philadelphia for a few months.
How did the opportunity at NRL (the Naval Research Laboratory) come about?
Totally by accident. We came to Washington, and again, I was just going to get a job somehow. I had no prospects. I came with nothing, except a degree. And people said that wasn't worth very much in 1972 (laughter)
So, you went to Washington before NRL came together.
Right. I went to Washington when Dan thought he got a job running a paralegal training program that he had to set up from scratch in Washington. When he got there, the program funding hadn't passed through Congress yet, so his first job was as a lobbyist for his job, which eventually came about. I, on the other hand, had no prospects, being a science person in 1972, when there was no market for scientists. It was an historically difficult time, so bad that the President even set up a special program for scientists. It was a kind welfare program (laughter). And this welfare program that he'd set up, this was Nixon, by the way, was one in which scientists who were trained in a field in which there no jobs could be trained in a different field that needed people. The various government labs in the area had fellowships they could give for this.
When I got to Washington, there was a range of possibilities but nothing definite. I think I could've programmed the computer for a company, I knew I could type, I could teach Fortran, or I could teach physics. But there were no apparent jobs to be had for a new PhD. Finally, I did run into this group of physicists at the American Physical Society April meeting, which was in DC, that was looking for people to work at the Naval Research Laboratory.
I started to talk to them, and there was this one group with whom my friend Joan was working. I went up to these people and said, "Look, if she can work for you, I can work for you, too." We had similar backgrounds. And eventually, I wound up working with that group in the Plasma Physics Division.
Now, you said you were less political than your husband. Were there any conflicts of interest just in terms of working in that kind of an environment at the height of the Vietnam War? Or it was a separate world?
No, no, no. No conflicts at all.
What was your initial work and affiliation? Was it a postdoc? Was it a staff position?
The war was over by the time I started working at NRL. It was sort of over while we were at the end of our stay in New Haven. I remember getting back from a trip, and Dan meeting me at the airport, and we were so excited that the War was over. But I didn't feel conflicts. There was only one time I felt a conflict at NRL.
This was very early. This is actually true. Shortly after I got there, I was asked to design a neutron bomb. "Go design a neutron bomb." Funny thing to tell someone to do.
This was Carter's idea of having it kill people, but not buildings, right?
I don't know that. It might've been the beginning of Carter. (What I remember of Carter at the NRL, is that all the hot water was turned off in the restrooms. In order to save energy, we couldn't wash our hands properly.) I don't know why I was told to design that bomb, and I had trouble psychologically doing that. I remember getting really stuck (laugh).
Yeah. Was it a postdoc or a staff position?
It was like a postdoc, but it paid more like a GS-12 starting position. It paid pretty well, which was so exciting for me- to have a job and earn money.
And what was your initial project when you got there?
Laser-matter interactions. I really don't remember details, except that there were a couple of atomic physics calculations involved, but that might have come later.
And this was more a basic science environment, an applied research environment? What were the goals?
A little bit of both. To quote one of my favorite characters from Guardians of the Galaxy, "A little bit of both." (laughter) The group was very well-funded essentially to model high-altitude nuclear bursts, to create large simulations of these explosions for which there was some data. So, it involved computing high-speed chemically reacting flows with a lot of interesting atomic reactions occurring in them, probably from nuclear through to chemical in the upper atmosphere. It was a really interesting program, actually. A lot of basic work: basic atomic physics, fluid dynamics, algorithm development for computers, some of the very fundamental things that people are using for different purposes now.
I hope to hear that this was a more inclusive and supportive environment than Yale.
It was a lot more fun. They needed results. That was the difference.
And who were the end users or the clients of this research?
The funding for that initial research came from the Defense Nuclear Agency, DNA. Now, it's called DSWA, Defense Special Weapons Agency. It was this government agency that funded this work, and it was really to compare the results of measurements that had been taken by flights through these nuclear events. Many years later, in 1991, I learned that there was an equivalent program in the Soviet Union at about the same time, which was run by a person I knew many years later, and they were developing the same technology. At a meeting, the code developer from Russia was actually trying to sell his code. This was after the Soviet Union collapsed.
Did you feel academically connected in this work? Were you publishing in the same journals, presenting at the same conferences, that kind of thing?
Well, as a graduate student, working pretty much alone, I wasn't doing much presenting or publishing.
But I'm talking about at NRL.
Oh, at NRL, we published in the journals, Physical Review, various applied physics, atomic physics journals, everywhere. Most of it was open literature. As you see, the elements that went into this kind of simulation were very fundamental. Algorithms for computing reactive flows, how to compute Bessel functions quickly. Some of the most progressive numerical algorithms, which that actually changed what we were able to compute, were developed at that time. For example, the first algorithms that could realistically describe a propagating shockwave and its interactions were developed at NRL and published by Jay Boris at that time. That's probably one of the most important things that came out from that work, and it was an invention that came from this project at NRL.
On that point, I'm curious about the Laboratory for Computational Physics. What were some of the advances in computers that allowed for this work to be done?
Well, computer became bigger and faster.
And what kinds of research questions could now be posed? When you joined the Laboratory in I believe in 1978.
The Laboratory for Computational Physics, LCP, was formed in 1978. I like to say we were thrown out of the Plasma Physics Division.
Oh, to summarize, a bunch of prima donnas couldn't get along.
Did you like plasma physics and did you appreciate its utility for NASA, astrophysics, and things like that?
I appreciated it. I never worked that much in some of the really esoteric aspects of plasma physics, that would be ionized but not totally ionized gases. I worked more in weakly ionized plasmas, such as the earth's upper atmosphere. And yes, I did appreciate what it was. Especially, by 1978, when I had done a fair amount of both ionospheric and atmospheric work. And also, by then, we had already had quite a bit of work in solar physics and creating some of the first models of solar photosphere. This involved nuclear reactions, not chemical reactions. So, I did appreciate what it was.
What was the work in computational physics at the Laboratory for Computational Physics? What new opportunities did you have at that point?
I'm not quite sure which computer we used at the time.
Was your sense that it was cutting-edge, that you had access to the latest and greatest?
Oh, yes. No question. Maybe not the most cutting-edge, but we were close. What we could do was often beyond what any other lab could do by '78.
When did the Center for Reactive Flow and Dynamical Systems start?
Well, let me back up a bit. This was formed after 1978, perhaps in about 1982, when we’d grown substantially. I was removed by a promotion from being head of that group in '88.
And you were the founding director?
Yes, director of that. It was a small group, but it grew. It grew out of bounds. Unfortunately, it had the flavor of me, which was in reaching into all directions and was becoming a little bit out of control, of course (laughter).
What were your motivations? What was possible as a result of creating this group?
I don't know if I even thought about that. I just thought of exploring all sorts of things we could explore with the computer. We had the ability, now, to do amazing calculations. Turbulence issues, we could deal with. We could simulate and learn what was at the heart of some of the fundamentals of shock interactions. And of course, all sorts of new types of calculations could be done when you added additional physics to shock physics. So new things to explore! Shock interaction with a vortex. That hadn't really been done. Very fundamental fluid dynamics questions could now be studied in great detail. The full impact of it didn't come for quite a few years.
What were some of the key research questions at this point in reactive flow?
Well, there were so many fundamental turbulence problems that could now be simulated. For example, you could simulate a turbulent flow, perhaps not perfectly, but well enough to understand some of the basic processes occurring. What was the structure of a flame? What was the structure of a detonation? What was the structure of a transitioning flow? What is the structure of the solar corona? How does a star explode? All of these questions could be approached. Maybe not really solved for many years but approached well enough to understand many important features of the flow. The complexity of the physics and the detail that was beyond anything that you can do before. And what was interesting was and marvelous was that every time you did a new calculation, you found something that no one saw before. Even the simplest things.
And I'm still finding that, by the way. Do something simple, and you'll see something that you didn't expect or that no one has seen before. That’s exciting. I guess the very first time we tried to do a two-dimensional calculation of a propagating detonation, and we saw how it died, it was in the early 80s, and it was a major observation. Because no one knew whether we were computing a numerical mistake or a piece of physics. So that's the way I presented it at a meeting. "Is this a numerical mistake, or is this a piece of physics?" (laughter) No sense putting your foot in your mouth too far. Then I wrote a paper, hedging it. I remember sitting there, and at that time, cut and paste was literal. I had to look for words I could cut out, and then I'd put them in with scotch tape. That's how I wrote that paper.
But I went through all the possible reasons why what we saw could be physical and what it implied if it were. And all of this meant quite a bit in that it changed the way people thought about that phenomenon and what a calculation might show. And then, we wound up doing some accidental calculations a couple years later of turbulent flow, which also had the same effect. Just to be able to do them, I had to do quite a bit of political work, I recall.
Well, I wanted to get funding from the Office of Naval Research, ONR, to do some particular jet simulations. I already had some funding from NRL, but I wanted to be funded by ONR, too. I went to ONR and talked to the contract program manager there the time, I think it was Don Liebenberg. He said to me, "Well, if we're going to fund you, I want you to go see John Lumley at Cornell and get his approval." (laughter) So I tromp up to Cornell, and I talk to John, and he gives it the okay, and we got the funding. And that was pretty amusing in retrospect. John and I became pretty good friends after that. A small but formative anecdote.
A broader question about NRL, did the end of the Cold War change either the budgetary or political environment at all? Did that register with you?
The end of the Cold War did mean major changes at NRL. For me, it was certainly major. The most amazing thing was when I wanted to hire a person from Russia- that was Alexei Khokhlov, into our group. I called up security and said to them, "Can I hire this person?" And they said to me, "Oh, sure, Russia's on the list of friends. It'll take about a year to get them a security clearance, just like a Canadian."
Different world (laughter).
Different world, yes. And then, I remember the day I heard that the Berlin Wall went down. I was driving from NRL home when I heard the news. I had to pull off the road. The Cold War made an enormous impression on me and us. I'd been to the Soviet Union a few times in the eighties. And it was quite a trip. Quite an environment. And I was also there in '89, '91, and once or twice after that. The changes were just extraordinary. Now, as far as our work was concerned, I don't remember it changing things much. I was pretty much funded to do basic research.
NRL had a very interesting policy. You were either in the basic research part of NRL or the classified part. And the first director that I dealt, Alan Berman, with did not let them mix. We simply got reprimanded if we tried to mix them. I remember giving a presentation where I wanted to use an algorithm, we had developed for image detection, and he said to me, "Uh-uh. I never want to hear you talk about that again." (laughter) For reasons I later learned. But we were kept very far separate. When he left and the Cold War ended, areas began to flow over into each other more.
I wonder how you dealt with the idea that reactive flow required a unification of so many diverse disciplines. There was engineering, the computer science, math. When was it efficacious for you to read up about areas that you might not have had much background in, and where was it simply easier to connect and collaborate with the right people who did have that background?
We were more inventing than reading up.
Because there wasn't any literature out there, you're saying? You were making it as you were going.
Make it up, just like I made up my thesis work. You have to invent it all. But then, after a while, I began to see where to go in the literature. For example, for certain test problems you wanted to do, maybe you go to experiments that might be obscure in the literature. I remember reading about computer structures, but much of the time, we were even building our own computers in the 80s. We used the computers that were given to us, but we also built them You just did it. That's a problem I had- I never had a good course in things I needed to know. I’ve gotten many awards, say the one in fluid dynamics. I never took a course in fluid dynamics, and this gives me an incredible inferiority complex (laughter). I never took a course in reacting flows. There were no courses in reacting flows. You made it up.
So, let's talk about some of the really diverse areas where this research had an impact. For example, biology, biophysics, biosensors. Where did you see that you had something to contribute to these fields?
Well, I've never really worked in cellular biology or these really small-scale biological structures. But people have used the computational techniques, the algorithm speed-ups, and all these other things that we'd been working on to create and find solutions of their model equations. What is this biological cell but a very complex, small chemically reactive flow with a lot of surface and viscous effects? Algorithms and approaches to solution have gone into diverse fields and been modified accordingly. A lot of the work that we had done in sensing, developing sensors, had to do with microfluidics and microfluidic flows. And these were flows, primarily water, maybe water with something in them, through very, very small.
This is a surface-dominated regime of very viscous flows. And in some ways, that's a very interesting fluid regime, “creeping flows.” If it's a gas, it's even more interesting because you can have a gas in a system which is very, very small, and it's a non-equilibrium flow because the mean free path is so much larger than the size of the system These non-equilibrium flow solution techniques were applied to microfluidic systems, gases and liquids. I tried once to set up a more global model of various human systems in a network-type framework. And that didn't go very far, but that's one idea of what you could do with some of these fluid systems. You have to remember, fluid dynamics is just everything.
Were you thinking about aerospace issues during this time, or that would only come later?
Combustion, engines a little bit. But no, that came later when we got into the scramjets work. And I think that was either late-eighties or early-nineties.
How did you get involved in that? What was the entree?
Well, we were trying to do accurate simulations of high-speed flows with shocks and shockwaves. And shocks, to get them right, required certain kinds of good, conservative algorithms, which were the kinds of algorithms that we'd been working on. Combining shock and reactions gives simulations of many types of explosions and blasts. And what is an engine but a controlled explosion? For a scramjet engine, you're trying to control the explosion, which means trying to control the shocks and the reactions.
It was a natural move into that when people started talking about, "Well, let's fly at Mach twenty-five," to look at these kinds of things. And then there was the SST, the supersonic transport, and the whole idea that we were going to try to design vehicles that would go at high Mach number. That was one of the cycles of hyper-sonics. We're in cycle three as far as I'm concerned right now.
Did any of this research have obvious industrial application? Was Boeing or Northrop Grumman following what you were doing?
Perhaps. I don't know. You see, at that point, that was before the merger of aerospace and–there's a very interesting history of fluid dynamics, which is not really written down. And it's two histories that came together in an “explosion.” One is the aerospace community, and they were not very interested at the beginning in compressible flows. They were concerned with slower flows. The algorithms they used were not designed to do the kinds of shocks and shock interactions that those of us from the bomb or astrophysics communities were doing. We came at these problems from the bomb and the astrophysics communities, which are very related in that both applications require the same kinds of algorithms for high-energy flows. At one point, there was a clash in the communities, which still seems to be going on.
Oh, I came from the bomb and astrophysics and communities. We were studying solar physics, astrophysical jets, high-speed combustion, and detonations and concerned with high-speed shocks and shock interactions. So then, when it came to supersonic transport and high-speed flow, the aerospace community had to begin to think about shocks, and planes turning transonic speeds and creating shockwaves, and physics in a regime involves shock waves. And a lot the solution method aeronautics used designed for that regime, and they had to adapt. As a result, there was a coming-together of the communities, where those of us interested in compressible flows had to added viscous terms and deal with boundary layers, and aeronautics had to admit that dealing with shock waves required a different kind of algorithm- conservative, monotone, causal, etc.
Now, speaking about astrophysics and even cosmology, the interplay in the field, are you doing research where it's you who recognizes the value of this for cosmological questions? Or were there people who were sort of more working centrally in that area, and they find out what you're doing, and it's them who make the connection?
I don't know, I'm kind of a dabbler in that field. Again, that's my science fiction field.
So, what was going on in cosmology where you thought you had something to offer?
Well, the astrophysicists were interested in astrophysical jets, which are large shocked, expanding plasmas, for example. Starting in the nineties, we became very interested in supernova explosions, thanks to Craig Wheeler from UT Austin and the Alexei Khokhlov who joined our group. From my point of view, this kind of explosion a very large-scale combustion process with nuclear energy release instead of chemical energy release. Much of the same or analogous physical processes are involved. We realized that you could even do experiments in a lab that would teach you the physics of what might be happening in a supernova explosion. We started doing these with Geraint Thomas from the University of Wales at Aberystwyth. There were analogies you could make between exploding starts and a spherical chemical explosion. The numerical techniques and codes that we developed were the ones that could compute a supersonic flame turning into a detonation in a laboratory experiment. If we could do that, could we do that from a little flame igniting in a white dwarf star, turning into a turbulent flame, turning into a detonation?
I thought of it as the same sorts of processes, only the scales and some of the source terms were different. In that case, it was more than analogue. Well, we were looking at problems with the same equations, the multidimensional, compressible, reactive-flow equations, but different source terms. We had to change the equation of state, we had to change the size of the system, and so forth. But it's strangely similar physics because of the nature of the equations you have to solve. We learned a lot. I don't know if I've answered your question. I looked at a lot of theories of the evolution of the universe from the Big Bang, and there was even one paper that compared the origin and expansion of the universe to something that looked like a detonation wave. The conversions of one form of matter to another didn't seem to me the kind of thing that we could model easily with the fluid equations. I spoke to friends working elementary particle physics, back at the time when I was interested in analogue problems, and they could not really tell me about the types of source terms we needed (laughter). Anyway, I dabbled.
What were some of your contributions in space exploration vehicles?
Nuclear engines, probably. Concepts on the feasibility of various schemes for nuclear propulsion, which has gone very different directions than I could have imagined. My contributions are most likely in the engine and rockets part of the problem. That part of the problem that involved high-speed reacting flows. I’ve done analyses on explosions that destroyed vehicles, more of a forensics approach to determine why an engine failed and sometimes why it might fail. What we did was the sort of analysis and detailed work that you don't normally read about.
I'm curious about your inspiration to write the textbook, Numerical Simulation of Reactive Flow. Was the idea that this was something that had reached a level of maturity where it should be taught with a textbook in college? Were there other textbooks that needed to be updated? What were some of the decisions there?
There were no textbooks. And there was nothing taught or clearly explained that expressed our approach to doing things. There was no text to explain the approach that Jay Boris, I, and others developed at the Naval Research Laboratory. We weren't really taken seriously by many people until they looked at that textbook and understood that there were rigorous mathematical and algorithmic underpinnings to the approach. Certainly, in the combustion community, the approach was not taken seriously until they saw it written out and explained. We'd show them a movie of the structure of some sort of event, and they'd say, "Oh, that’s a nice movie, but what's the relation to anything I care about?” Honestly, I had no idea that the book would change anything, and I don't know exactly what the driver was to get that written (laughter). It was not easy. And you'll see there’s are lot of very opinions written in that book and that caused some problems among our colleagues.
Did you see your role at NRL as really making the NRL a nexus of reactive flow research? Or were there institutions that were other nodes, and you were a part of a larger network?
I think my point of view was probably different from most people. I always looked at things in terms of survival. Surviving graduate school, surviving being an undergraduate, surviving high school, all of these (laughter). Well, if we were going to survive at NRL and in the communities we were in, we would need to make a name for the group as a whole. Well, we would go to meetings, we wrote lots of technical papers, we do the usual things that would let people know our group existed. other people don't do. And at one point, I realized we really had to write it down. First, we wrote a review paper and from that, we were asked to write a book. But the format of a allows much more analysis, more detail, more information, more opinions than a review paper. I think I was going after legitimacy that would lead to funding and a that would allow the group to survive.
You mean external funding beyond what NRL itself could provide?
Oh, of course. We had to bring in funding from outside for projects at that point. We could not be totally funded by a rather limited internal budget.
And so, who were some of the key supporters? NSF, DOE?
No, NSF would not give us money. Some parts of DOE, some parts of NASA, some parts of ONR, some parts of this, some parts of that, all would fund us (laughter).
This is not a science question, this is just a living-in-the Washington area question. What was 9/11 like? What was that day like for you? Where were you?
Oh my gosh, that's an amazing question. I was driving from home in Virginia up 295 into Washington. And I noticed that the other side of the road, coming out of Washington, was blocked by an accident. There was no leaving Washington at that point on that road. There are only a few main arteries in and out. At that point, I didn't think twice about that accident. And then, when I arrived at NRL and looked at the TV that was up in the main entrance of our building, I saw that they were showing, over and over again, this plane hitting the tower. And so, I said, "Oh my God. A drunk pilot." But then, as I was watching, they showed the second one plane hitting. And I said, "Uh-uh, that's not some drunk pilot. We have a situation." I went to my office, and the first thing I did was call my nephew, who worked in the area. He answered and said that he was in the building next to the World Trade Towers, and he was being evacuated. All I could think to say was, "Give me a call when you get home." (laughter) (What else was I going to say? "Give me your last words, darling"?) He said he was watching people jump from one of the Towers.
He called three or four hours later, after he had gotten through quite a bit of debris and body parts to reach his apartment. Then I was sitting in our conference room waiting for the third plane to hit somewhere in the vicinity. It finally did hit the Pentagon, which as the crow flies, is not that far from NRL. I heard or felt the shock when it hit. As this was happening, I was getting calls from all over the world, even Russia, saying, "What's going on? Are you OK?"
Finally, after most of Washington was evacuated, I left and went home. Luckily the blocked road out was unblocked. I was wondering if that blockage was purposeful, but no, it was just a normal accident. When I arrived home, everything was very quiet. It was the quietest I'd ever heard. No traffic, just birds. It was a lovely day for a walk around the neighborhood, but it was very scary. The whole thing was very scary.
Of all of the things that 9/11 was, it was a day of combustion. I wonder if you ever thought about that in a scientific context.
It was a day of shocks in many senses (laughter). Yes, it was combustion and explosions, it was a violation of aerospace.
Did you ever get involved in any of the studies about how the towers fell or any of that stuff?
Yes, I did. Many years later, when I taught a course at the University of Maryland. I invited colleagues to talk who were on various sides of the story of why and how the different towers fell. It was analyzed very, very thoroughly by a lot of people.
What surprised you, and what made sense, given what you already knew about how and why the towers fell?
I did not exactly know what triggered the falling, or the details of what went wrong. Well, in terms of the combustion what surprised me the most was that the initial computations or analyses did not take into account the combustion of the material in the various rooms that caught fire. I’m not one hundred percent sure of this, but including this extra burning mass think that the analysis of what happened.
But I guess more than thinking of it as a combustion phenomenon when it happened, I was really taken by the response of the world to it. Some people from other countries actually said, "Well, it's your fault, you deserved it," meaning we in the US, and some people said, "Oh my God, this is terrible. Are you OK?" It was socially and personally very upsetting. Oh, and then, I heard from a friend, who was working in one of the military complexes right near where the Pentagon, and who was in her office with a very highly place Army General. The plane that was crashing into the Pentagon flew directly over her office. She said, "At that point, the Generals only had CNN to tell them what was happening.” That surprised me.
Did 9/11 change your research agenda at all?
Short term, yes. Long term, not sure. Short term, all anybody could worry about were ways we could cause havoc in the United States. "Let's think of every possible way we can cause havoc in the United States and destroy something, and then let's have a plan in place to stop it." It was frantic, and it lasted awhile. And there were whole committees and meetings on this topic, meetings where you were urged to be creative and think of scenarios. But long term, I'm not sure it changed research directions that much. What it changed more was the environment of research. It closed down, became less open. 9/11, I think, is when we started to close ourselves in as a country. And that was very bad for research.
When did you start thinking about going emeritus at NRL and thinking about pursuing academic opportunities? Or I should say traditionally academic opportunities?
Well, the first time I thought of that was actually a long time before I made any moves on it. It was in the early nineties when I decided, "Maybe it's a good time to leave NRL." But I didn't. It didn't work out.
Did you do any adjunct teaching? Did you have a teaching bug that you were able to fulfill at NRL?
I always did a lot of teaching for postdocs and graduate students at NRL. We had quite a few graduate students in residence before 9/11, mostly they were international, from France, Belgium, England. We were quite an international environment at that point. For many years I worked with colleagues at Michigan, in the Aerospace Department. These were people like Marty Sichel and Jerry Faeth. I first started at Michigan as an adjunct professor in about 2005. The was arranged by Jerry Faeth. Unfortunately, he died just before I actually started. I did want very much to go there to be on the faculty. If I had not gone to Maryland, I might've gone to Michigan. Or if I had not gone to Texas, I might've tried to go to Michigan. I liked the department and the work there very much. I thought about leaving for an academic position every time things became, well, difficult at NRL, which happened every few years before I did leave. Perhaps a few years before I left, I realized that it was definitely time to leave. The reason for retiring that I gave people was that I was too old to die (laughter). And that’s meant to be taken any way you want (laughter).
Now, was this more about new opportunities for you? Were you not happy with the direction that NRL was taking at that point?
Oh, NRL was evolving. It was changing. And there was a change of administration, and an imposed or forced change of administration more locally in our group. Rather than atrophy and be pushed into a corner to fade away, I just said "Here's an opportunity to try something else." I thought I would either try academia or go into industry. I considered the aerospace industry, but that really wasn't me. Academia was a better fit. And Maryland was very accommodating, for which I really need to thank the dean, Darryll Pines, for helping me to make the transition,
Was that part of the attraction, that you could stay local?
Yes. I could stay local, but finally the commute got to me.
Because you were in Virginia.
Yes, it's a dreadful commute. You either go through the heart of DC, or you go around the beltway. One is nerve-wracking, the other is nerve-wracking. Every time I'd get home or get to Maryland, I'd say, "Phew, made it."
What department did you join in Maryland?
It was Aerospace Engineering. At least my main department was Aerospace Engineering, which was a very good department for me.
And to go back to the beginning of our talk, was it specifically Aerospace Engineering that you were looking for in academic positions? Did you understand at that point that that was sort of the nexus department that was most capable of housing all of your diverse interests?
I think the Dean realized that. I thought it was fine. I was willing to consider almost anything, to be honest. Physics, astrophysics, mechanical engineering. I wouldn't have minded any department, I think. But I think the Dean decided that I could do the most in Aerospace. Because I was actually already in the National Academy of Engineering, and my main section there was aerospace.
Did you take postdocs and graduate students with you from NRL?
A postdoc came. There were no graduate students at NRL at that point. Everything had closed down after 9/11.
So, this was the same research agenda, but you're doing it in a new environment? Or to what extent did you take on new research as a result of this move?
Yes, and yes. A very, very good researcher came with me as a postdoc, Ryan Houim, who is now at the University of Florida. And I was able to bring on another post-doc from China, who I couldn't have come to NRL after 9/11, that was Huahua Xiao. Huahua worked with me for a number of years. Eventually, a colleague from NRL retired, Carolyn Kaplan, who came and worked with me at Maryland as a research professor. Then I had a quite a few graduate students there. It was actually at Maryland where I got a chance to work with Michael Gollner, who's now at Berkeley. I was new there, and he was a relatively new assistant professor who came a year earlier. So, he taught me quite a bit. And he was an experimentalist, so we began doing some really good work together.
What did you work on with him?
Well, that's another interesting project. Do you know what a fire whirl is?
A fire whirl is a vortex, imagine a tornado, but besides being powered by this swirling flow, there's also some energy release in it, which makes it a very powerful force. It’s a swirling, reacting flow. Fire whirls occur naturally in forest fires, wild land fires or bush fires, where they can be a couple kilometers high. You can make smaller one in the lab, even very small ones. But a couple-kilometer-high whirling fire tornado is not something you ever want to meet. In the field, when a fire spawns a fire whirl, there's only one thing to do, and that's run. There's no easy way to handle this force. I became fascinated with fire whirls, and Michael was fascinated by them, too.
We spent a lot of time talking together and designing little, tiny experiments that we could do in the lab to see how fire whirls behaved. It's very hard to simulate their behavior. Some years earlier at NRL, I had tried to do this, but I ran into barriers and didn't have the resources to follow through. We had a friend, Forman Williams, who has been Michael’s advisor at UC San Diego, who was a theoretician who did some work on fire whirls, but to me, the theory didn't make as much sense as an experiment and a simulation. It was too idealized. So, Michael and I started playing with fire whirls. And we said, "Well, maybe we'll get two little ones that talk to each other." Which was ridiculous, as it turned out. But I also had this belief that fire whirls were much more important than they were given credit for. If you looked at one in a fire, it was the dominant thing you saw, this huge elongated fire, way over the general height of the fire, going up into the upper boundary layer. And we knew that fire whirls throw fire brands which help spread the fire.
I thought they were important and that their importance was not acknowledged. I wondered if this whirling flow was a much more fundamental object in a fire. And then, because of this fascination or obsession with fire whirls, someone sent us a movie of a fire whirl that was formed in a lake in Kentucky when there was an electrical storm, and some lightning hit a storage facility at a Jim Beam factory. And a large amount of whiskey spilled out onto the lake. Thousands of gallons of whiskey. Imagine what that smelled like when the lightning hit it and started a fire on the lake. But the fire whirl on the lake, and you can get this movie if you want, was a beautiful whirling fire, not on land, but on water, so it was an interesting fluid dynamics problem. You could see how the swirling surface pulling fuel into the fire, and then cleaning up the fuel on the lake what seemed to be faster than it if there were no the water that made a smooth, more easily movable boundary layer.
This led the idea of using fire whirls for oil spill remediation. Huahua Xiao, Michael, and I came up with that idea, which has now has actually become a project sponsored by the government agency, BSEE to develop this idea and apply it on a large scale. Then we started experiments on a small lab scale to find out if fire whirls were quantifiably more efficient than regular pool fires, and whether they were more efficient on water than on land. And that's when something absolutely incredible happened. And this produced the discovery that that went viral all over the web. We had created fire whirls about two meters high, about this wide, in a dish of water. Soon after we started the project, that is, created a fire whirl burning heptane on a pan of water, the fire whirl changed. First, seemed became stronger, and stronger, and stronger, and stronger, reached a stage where it was a fast-whirling column of burning fire. Then it started to change its shape.
It went from a two-meter-high violent, turbulent flow through some shorter intermediate states, which at that time we could not diagnose, down to this tiny, little whirling blue top-like flame a couple inches high. It changed from yellow to completely blue. A beautiful blue spinning top. It was absolutely gorgeous. None of us believed what we say. Ajay Singh, Huahua, Michael and I, when we saw this we literally screamed, "What is this thing?" We'd never seen anything like it. No soot at all. And it was burning a relatively heavy hydrocarbon liquid, heptane. Well, we subsequently tried other things, including whiskey (laughter).
Well, I'm sure you had fun.
We had great fun. We tried rye, octanes, heptanes, crude oils, all sorts of fuels and fuel mixtures. We almost burned the lab down once when too much fuel was poured on the water. But we could always get this tiny, little blue flame, a perfect flame with no soot. Subsequently, we found out that it was burning almost all of the fuel on the surface. The blue whirl would just burn everything all up, and then die out very gently and calmly. Well, no one had previously reported seeing this persistent, tiny blue whirl.
Then, the issue came to naming it, and I won that vote. We called it something very simple and easy to remember, the blue whirl. If you look up “blue whirl” on google you find an eggbeater. If you look up “blue whirl fire,” you'll see movies of the blue top-like whirl burning fuel. And it was beautiful. It went totally viral. And it was all from fooling around in the laboratory with fire whirls.
The technical issue became, "What is this then? Why hasn't anyone seen it before? Will it burn any liquid hydrocarbon totally cleanly? You don't have to gasify it first, just throw it on top of water? This is awesome. science fiction? In fact, it was real, but there were a lot of science fictiony little drawings on the web about it, and they were imaginative but not realistic. Right now, we have programs with NSF and Army to try to understand the structure and dynamics of the blue whirl and the transition to the blue whirl by trying to simulate it numerically, work started by Joe Chung and Xiao Zhang for their PhD theses at the University of Maryland, and now Xiao is continuing doing in a post doc with me here at TAMU. There are also experiments in the Army Research Laboratory by Paul Anderson. Michael continues experiments with Ram Hariharan and other students at UC Berkeley. One thing we are looking at now are the effects of wobbling the blue whirl, and we are doing this by simulations. Michael is now leading the original work to study fire whirls for oil spill remediation.
To go back to an earlier question, where was the applied science, and where was the basic science in this project?
Very good question. The basic science was, what is this? What is its structure? Why did it form? Why is it working? How did it form? It actually turns out to be a rather complex “fluid dynamics combined with reaction flow” question. Its development is related to a number of fluid instabilities. One of them is called vortex breakdown. This instability is important in many fields, not only aerospace. I've even heard recently that it has applications to issues related to Formula one. But when a fire whirl makes the transition to the blue whirl is, it undergoes some form of reactive vortex breakdown. That's starts the transition. It's a very beautiful process. Pictures of it win art contests. In fact, we've won every art contest we've put this into (laughter).
So that's the basic fluid dynamics coupled to chemical reactions. The applications, well, I don't know. If we can control vortex breakdown, we have an application. If we could help figure out how to control it for Formula one problems, we have, perhaps, a surprising application. If we can control it on aircraft wings, we have a good application there, too. So that's a fluid instability, which is important in aerospace. And it's probably a new area for reacting flows. And again, no one knew what that flame was. Perhaps someday it will be in a combustor.
What guidance does theory provide for something like this?
A lot. Subsequent theory. First of all, vortex breakdown, there's some limited theory for this, but not a lot to guide us here. We could say there might be some vortex breakdown in this swirling flow, but this doesn’t tell us how it's going to break down and what the intermediate and final states are. We just know that it might transition under certain circumstances, but there could be a number of final states. Simulations are the only real peak into the flame and its structure that we have. There is also some theory, now, on swirling flows. To me, the simulations and experiments were the most useful for understanding this phenomenon.
On the undergraduate side, did you welcome the opportunity to teach?
I really didn't teach undergraduates unless they came to my class.
Was that by design?
It just happened naturally. I never had the opportunity. It was primarily graduate students that gravitated to me, and I guess I gravitated to them. I think that those were the people for whom I could do the best. Although, I enjoy teaching. I have no problem teaching. It just doesn't seem to be what I do.
Did you remain connected at all with NRL? Or was that a clean break?
No, for a long time, I was connected. I still have connections there now. But in time, there was more of a break. The younger people who remained there have now taken over, and they're leading the show, particularly in now hyper-sonics.
What's a good example of it being advantageous for you to retain that connection with NRL? What can you do as a result of that affiliation that would not be possible absent it?
Make phone calls and find out what's going on there.
Obviously, interesting stuff is going on there.
Yes. Advantageous, no. I think they'd find it more advantageous to deal with me when they do. I like to keep in touch with friends, and particularly my former post-docs, graduate students, others who I hired when I was there, and who are now running a lot of the show. Two of my former students have major programs in hyper-sonics in one division, and there are others working on the computational side. So, I see them doing very well, very independently.
Now, there's never a grand plan, but when you got to Maryland, did you think that that would be your last full-time position? Were you surprised when the opportunity at Texas came about for you?
Well, you ask good questions, David. I thought I'd be at Maryland until whenever. I had no plans to leave or stay.
You were happy there.
Yes, kind of. I became more restless as I realized that they really didn't think that my areas of work were ones they wanted to promote. By the time I left, I began to feel boxed in the same way I felt at NRL when I left. "Maybe this is not a place to start the kinds of things I want to do or continue them." They said they wanted me to stay, but they couldn't offer what Texas A&M offered. And I welcomed the opportunity to have a real “old-age adventure,” I called it.
Was there somebody at A&M who was driving the recruitment? Somebody there that you really wanted to work with?
No one-body, there were a lot of friends there. There was nobody I particularly wanted to work with, just friends I thought I'd be happy being around. A number of friends who had gone there before me, and they were instrumental in my coming there. Dick Miles came from Princeton, and he'd been a friend for many years. Antony Jameson came from Stanford shortly before I did. He is a computational algorithm person, and that was great fun for me to be around him and his family. Bonnie Dunbar was a very good friend of mine, and she was there. All in aerospace. And so, I felt like I had as many friends and potentially more people to work with than I had at Maryland, to be honest. Michael Gollner had left Maryland for Berkeley. Jose Torero had left Maryland for UC London.
What was the magnetic pull of all of these people to A&M? What do you think that says about the university more broadly?
Money. This means opportunity to do something you might never have an opportunity to do. For me, the opportunity was this detonation tube. When we had the last one, it was taken away by circumstances before it reached its ability to give us all of the answers, we wanted to get from it. The same cranes that came and put it together came and took it apart. Government bureaucracy, I think, and many really sad people. And TAMU said, "Oh, yes, you can build one here. If you can't build that, you can build a computer lab. Here are the resources."
What explains the budgetary environment at A&M? Is it a dean? Is it government contracts?
The governor, the chancellor, and the dean are all very go-getting people, and the university system and government put a lot of money into education and recruitment. I think that they're interested in the kinds of work I do. I believe that a lot of the funding of the enormous Texas public educational system is based on oil money. There are legends or stories about that. They have their resources, and they put them into education and recruitment. With my position there, there are a couple of other opportunities to hire younger people. And that's what TAMU also wants, to build groups and competency.
It's a very forward way of looking at education, developing an educational system, putting resources into it. And in this case, they're putting them in through people that they recruit at a higher level, who then bring in other people to the faculty. These opportunities are competitive for Texas universities. They're called GURI CRI positions. GURI stands for Governors University Research Initiative and CRI is Chancellors Research Initiative. It’s a combination of governor and university funding, and it has brought many of my friends inhere There's a feeling when you're here, opportunities open.
So, you get to College Station. What's the game plan? How do you set up shop, given the fact that you have the resources to do what you want to do?
Wow, that's a question. How did I do it? Well, before I knew it, I had a reasonably sized group (laughter). There were groups, hangers-on to groups, groups of groups. I don't know, it just happened. I really thought at the beginning, "I'll just hire a couple of postdocs, and we'll do some work." But before I knew it, I had four or five graduate students, two postdocs, and all sorts of collaborations all over the university for experiments and calculations. I felt as though things had suddenly changed. Everybody seemed to want to interact, and they generally followed up. I wasn't used to this. So as usual, I just let whatever happened happen.
Was there a singular research question that sort of tied it all together for you at this point? What were you most interested in?
Well, I have a question. It's not the most important question, but it is a basic science question. There's a property of detonation waves. In some system, if you try to start one, you will not be able to do it. But if you make the system larger, you can get a detonation wave. If you make the system even bigger, but you can get a detonation wave in even more dilute systems. Something this size won't sustain a detonation, but something this size, will. Something that won't detonate in this size will detonate in this size. And so on, and so forth. So, take the Earth's atmosphere (laughter). How much methane is there in the earth's atmosphere? Look at the percentage, and say, "How high do you have to have this distributed in order to have the Earth atmosphere detonate?"
That's not the question, but that's my joke question that I have posed. The real technical issue is that what is changing is the fundamental size of the structure of the substructures in the detonation, and what is changing as a result of that are the limits at which it can be created. So, you can be looking at a very, very lean, mixture and only get this substructure to form if your system gets bigger and bigger. I want to know how far you can go. I want to know if you can create detonations that will exist in regions where you can't have a normal flame. I just want to know what the limits are.
Just to know, not because it has any particular application to anything.
Well, it might have an application. It may have some very fundamental cosmological applications. But I did ask one or two famous theoreticians, "Can you have a detonation in a lean regime where you can't have a flame going?" And they said, "I don't know. I don't see why not." Well, I can think of why not, and I think they could, too. But I want to see how far you could go (laughter). So that's one little thing I just want to find out.
Where is computer simulation in this? What needs to happen physically in the lab, and what can be simulated on the computer?
We can simulate a lot more than we can measure right now. And we've done that for a number of types of problems. But we don't know if the simulations are giving the right answer because there are some changes in the controlling processes as the size increases. I don't know if the results we see are they're physical or numerical. And we'll be able to find that out, hopefully at some point with this experiment. You can take calculations so far, but if you don't put the right physical processes, you don't get the right answer. And for practical problems like detonate-ability, explosivity of materials, behavior of the materials under stress, you don't know it all. You need an experiment to check it out.
We’ve been able to check the simulation results for small systems. And we've even tried to check them for one-meter systems. But not two meters, not ten meters. There are interesting things that happen at the larger sizes, but they still involve small-scale phenomena. It's not like you're losing any small-scale effects when you look at the larger ones. You just are extending the ones you have to consider more.
I wonder if you can reflect a little more broadly in some of the advances in numerical simulation that might be relevant for this.
Right. Well, to do some of the things we want, we've most of the basic techniques. Thanks to the work done in the early the seventies, we can, with great confidence, compute shocks and shock-shock interactions, at least on a macroscopic scale. In fact, we can now give codes to students, and they can go play with it and learn a huge amount of physics of fluids. The next thing you need to be able to compute these is mechanisms for chemical or nuclear energy release, and how these change with time, position, and background conditions.
We have a pretty good idea of how to deal with chemical reactions as long as the pressure's not too high and there are no shocks around. But as soon as you start shocking materials or changing the pressures to twenty atmospheres, even ten atmospheres, we don't know the chemical reactions that well. There are non-equilibrium intermediate states, which are important, and we don't even exactly know which ones they are. Standard chemical models don't work. Whereas we do have a pretty idea about the chemistry of hydrogen and a reasonable knowledge of hydrocarbon chemistry. But the kind of reactions that happens in a pressurized, high-speed reactor, where there are shocks and shock interactions.
We really need to know what's happening in these non-equilibrium chemical situations, such as those that result when a shock goes through a reacting material. That’s why I'm hoping that applying some of these incredible laser diagnostics, say, such as those Dick Miles and other people at AMU have, we can maybe be able to look into one of these systems and at least learn a little more about what is happening. To get around this lack of information for now, we've been very clever and invented ways of integrating our lack of knowledge with some known experimental results into the model so that we can at least get the right answer.
And what is the time scale? Best case scenario, where might you achieve some finality to these research questions?
Never. As soon as you figure one thing out, twenty other things pop up.
And things that you couldn't have even thought to think of before you figured out the first thing.
Of course. You know what I keep thinking of? It's like diving. You jump into the ocean with all this junk on you, the tanks, flippers, wetsuit, everything else you're wearing or carrying, all this paraphernalia. You jump in with these weights on, you let the air out to sink to some depth. And then, sometimes you have to ask, "Where am I? Which way's up?" So, you follow the bubbles. So, for me, the whole exploration into unsolved problems is very much like following the bubbles.
So, in a reasonable time scale where you want to enjoy the satisfaction of finding out something, what is it that you want to find out, and when might you get there?
Oh, I would like to find out the limits of a detonation forming, what determines it, if it's chemical, and what kind of chemical. Is it something we can compute? Is it some non-equilibrium phenomena? That's a little thing in some sense, and a theoretical thing I can know the answer to. There are a lot of big questions I would like to know the answer to, but I don't go after the big ones. What gives you the answers to the big ones are all the little ones. I follow the little bubbles.
What are the big ones? What kinds of questions represent big ones for you?
What does the universe look like? Does the Hubble constant make any sense? What happens if you really perturb the Einstein equations? Can you rip pieces of space apart or off? What kind of energy would that take? Those are big questions. Those are questions you can't even address because you don't know the physics to even put into the model. You do the best you can. Those are very hard questions, and some of those are science fiction questions. I tend to work in science reality more.
Have you had more opportunity to engage with undergraduates at Texas?
Not yet. I hope so soon, after the pandemic's over. I'd like to get a lot of them involved.
Teaching and to get them into the lab.
Yes. Or get them onto the computers, doing calculations, inventing algorithms, that sort of thing. I like to separate the science fiction from the reality that might actually wind up helping somebody at some point or helping to design something practical. Two different worlds.
Well, that brings us sort of right back to the beginning, where it was the science fiction that got you into so much of this.
The science fiction keeps me in (laughter).
Well, on that note, now that we've worked basically right up to the present, for the last part of our talk, I'd like to ask a few broadly retrospective questions about your career, and then we'll end looking to the future. So, I'd like to get your take on how you might have turned your negative experience as a graduate student without the mentorship, with all the hostility, into a very positive response, specifically in terms of your research agenda. In other words, perhaps with more direction, more mentorship, you would've taken a narrower approach to your science. I wonder if you can think about that.
Right. And I think I would've taken the approach to science that any mentor would've given me. It's just that there was none in graduate school. If Yale had been different, it certainly would've changed the kind of science I went on to do, at least immediately. The approach I took was what I saw at NRL, where I had mentors. The people there were more colleagues than mentors, and I just followed in their footsteps. I was lucky to find a good position after Yale. I just took advantage of the computing and physics I'd learned as an undergraduate at Bryn Mawr, both as a graduate student and when I went to NRL. And I think the negative experience I had is what made me so sensitive to the problems of the people I'm working with. There are some parents who were mistreated by their parents, and therefore, they mistreat their children. I tried to be the opposite. I certainly wasn't treated very well in graduate school, which was a full five years of my short life back then, but it made me very sensitive to how other people are treated.
I wonder if you can reflect on the two-way street that's such a hallmark of your career, and that is the way that your research serves as sort of a hub with so many spokes to other areas of science and where you draw on those other areas of science to propel the research that you're most interested in.
Well, I do tend to just be interested in a lot of different things, almost with no preference. I’m interested in physical mechanisms that explain why things are the way they are. What a lot of people don't see are that there are connections in many fields to other fields. I’m primed to see those kinds of connections. So, I take advantage of those connections to bring one piece of one field that's relevant to another field. I could bring the fluid dynamics I knew to microfluidics, to design of sensors in creeping flows, for example. It's just a matter of knowing some of the fundamentals cut across different fields, which may have been artificially separated by departments and journals and conferences. That's all I can say, you just learn a lot of stuff, and then you see where the bubbles go. I can't tell you exactly how to do this. Just like I can't explain to you the way I did physics problems, which was to sit there quietly, essentially go into a trance, and then come out with an answer.
What's been the most fun of all the projects and collaborations you've done? Whether it's basic science or applications.
Whenever I figured out why something happened. How two things interacted, and what the result was, I think, "Wow. No one else knows this." (laughter) I saw how that shock interacted with that boundary layer. "Wow. And that's what did it." These sorts of insights came from the numerical simulations, or theory, or experiments. That's what I love. Saying, "What is that blue whirl? Why is it? What's going on there?" And then, saying, "Well, maybe it goes through vortex breakdown. Well, maybe we can use energy release to control vortex breakdown. Yes, there’s an application." So, it's just being able to follow the bubbles. Wondering how something happens, and then it either turns out to be something interesting, or it doesn’t.
Have there been problems that have gnawed way at you, but no matter what you do, you just can't find an answer?
Yes. A lot of mathematical ones. Every time I think I've found a solution to something, I haven't. Usually, if I can't find an answer, I go away from the problem, and eventually, I might come back to it with an answer. When I’m not consciously working on a problem, and I don’t have an answer, I know that the proper connections are not made. It may take a ten or twenty, thirty years until I get the piece, but sometimes the piece appears. I've come up with reasons things happen twenty years after we had the problem (laughter). Just because we've figured out a little missing part.
Of all of the graduate students and post-docs that you've had who have gone on to so many interesting careers, what do you think are some of the connecting threads that might explain both their success in working with you and their success in applying science in their own careers?
The ones that have been most successful are brilliant, and they work hard. That's just it. I don't know what's driving them, but something is. Curiosity. A desire to give something new to the world. A desire to learn something or create something. As I said, they are curious, and some are just brilliant. I don't like to work with anyone who isn't brighter than I am (laughter). That's no fun.
Right at the beginning of our talk, I asked you about this notion of having a home department, given how interdisciplinary you are. I wonder if I can broaden that out and ask if there are any scientific concepts, thermodynamics, stat mech, whatever, that no matter what it is you're working on, really inform your worldview in science, the way you go about setting up a simulation or an experiment, the kinds of questions you ask, the feedback that you're looking for to come to conclusions.
For me, there is no best approach. It's just: don't focus. Leave it open. Let it come in, let it form, let it come out. I know this sounds like the wrong side of the brain is working. But I like to just the ideas spin around, and eventually, something is going to come out. (I do have a problem, which is a left-right problem. The left side and the right side, I don't know the difference. I have tricks to remember which is left and which is right. And I write with the left, and I write with the right. But when I try to write with my left too much, I start to get even crazier. My husband says my brain is not connected correctly.) So, I think the best approach for me is not to try to be extremely rigorous in setting up a path, but to let it flow ahead of me, and let it evolve spontaneously. So, I can't give you a prescription or a path to follow. I can't give you a field. It's the way my brain works – or doesn’t.
To go back to when you were explaining the role of computers during your time as a graduate student and how obviously primitive they were compared to where they are now, I wonder if your sense is that you're asking fundamentally the same questions you were asking in graduate school and that the rise in computational power allows you to ask and answer those similar questions, or have computers changed in a way that you can ask entirely different questions and have a different approach as a result of those advances?
Yes, you can have an entirely different approach as a result of those advances in computers. When I was back in graduate school, there was no such thing as simulation. You solved the set of model equations if you could, and you said, "This is the answer," and you drew a curve. Now, you'd look at the entire time evolution of the system in every little detail you can. You can see how every acoustic wave, or reaction wave, or particle moves. You have detail you never had before. So now, the issue is how to synthesize that detail and get the picture out. Back then, it was to generate the model to draw the curves to make the plots go give the more global or final results. It’s an entirely different way of thinking, it's called numerical simulation.
So much of your motivation, of course, is in basic science. What has been most intellectually or even societally satisfying to you in thinking about the ways your research has contributed to any number of real-world applications?
Yes, it is rewarding to have made contributions. Most people don't even realize that what they're using has a long history and the result of many small contributions. That's an interesting thing, people now don't know where common things come from. They don't know the history or the background. You're the science historian, David.
I'm doing my best.
There's a lot of interesting science history of ideas that has not really been recorded. So many students have not idea of the origin of what they're doing. Recently, some Air Force scientists were having some strange results in engine ignition. And it was so obvious to me what it was. It was the same phenomenon we computed for the mining industry when they asked us to tell them what the pressure was on this wall that they had created. It was the same physical phenomenon that was causing the engine to ignite sooner than they expected. That was really funny to me. I enjoyed that a lot.
It's nice to see science being used. It's good to see science being advanced so greatly from what the original, rough concept was. Now, that is something which I am proud of, how our group at NRL really invented, in some ways, reactive flow. We defined it, we said what it was, how it was different, why it was important. We did all of this very early on. And now, there are people advertising jobs in reactive flow. Not just me. So that feels good. I guess I'm more excited about the terminology than substance (laughter).
You know it's a real field when people can get jobs in it, right?
Yes, or you know the importance you believed it had is recognized by others.
Perhaps it's more accurate to say that you synthesized a lot of disparate fields that people weren't thinking to put together in the way that you did.
Right. And the main issue, of course, is that we describe this on the basis that the same equations are solved. All that changes is the scale and the source terms. Of course, that's what defines the problem, the scale and the source terms (laughter). But the solution techniques are the same.
Last question, looking to the future. What else do you want to accomplish? What's most important to you for however long you want to remain active?
Not to become inactive.
You're already too old to retire, as you say, right?
Yes, too old to retire. I want to be in a good, comfortable environment where with minimal anxiety, and where I play with a lot of different ideas. I like traveling. I want the same things everybody wants. To be around good people, have a good glass of wine. Just to enjoy each thing as it happens. I know that I'm not going to discover the origin of the universe. And I'll never be able to tell you whether there's a God or some kind of mastermind out there, or why you in particular wear brown glasses, or anything like that. But I might be able to enjoy figuring something out, or those trees I see behind you, or life for the next hour or so. That's a rather narrow view, isn't it?
But it's one that's also quite realistic. Elaine, it's been so fun spending this time with you. I'm so glad we connected and were able to do this. Thank you so much for doing it.
There is a high babble-content to this interview. Well, I hope I haven't babbled too much.
Not at all.