Gravity-Capillary Lumps Generated by a Moving Pressure Source
James Diorio, Yeunwoo Cho, James H. Duncan, and T. R. Akylas
The nonlinear wave pattern generated by a localized pressure source moving over a liquid free surface at speeds below the minimum phase speed (c) of linear gravity-capillary waves is investigated experimentally and theoretically. At these speeds, freely propagating fully localized solitary waves, or ... [Phys. Rev. Lett. 103, 214502 (2009)] published Fri Nov 20, 2009.
Multibubble cavitation inception
Masato Ida
The inception of cavitation in multibubble cases is studied numerically and theoretically to show that it is different from that in single-bubble cases in several aspects. Using a multibubble model based on the RayleighPlesset equation with an acoustic interaction term, we confirmed that the recentl ... [Phys. Fluids 21, 113302 (2009)] published Thu Nov 19, 2009.
Numerical simulation of liquid sloshing in a partially filled container with inclusion of compressibility effects
Y. G. Chen and W. G. Price
A numerical scheme of study is developed to model compressible two-fluid flows simulating liquid sloshing in a partially filled tank. For a two-fluid system separated by an interface as in the case of sloshing, not only a Mach-uniform scheme is required but also an effective way to eliminate unphysi ... [Phys. Fluids 21, 112105 (2009)] published Thu Nov 19, 2009.
Unsteady Velocity Profiles in Laminar and Turbulent Water Hammer Flows
Alireza Riasi, Ahmad Nourbakhsh, and Mehrdad Raisee
The behavior of unsteady velocity profiles in laminar and turbulent water hammer flows is numerically investigated. In this way, the governing equations for the quasitwo-dimensional equations of transient flow in pipe are solved by using the modified implicit characteristics method. A k-omega turbul ... [J. Fluids Eng. 131, 121202 (2009)] published Thu Nov 19, 2009.
Flow Separation Control on a Race Car Wing With Vortex Generators in Ground Effect
Yuichi Kuya, Kenji Takeda, Xin Zhang, Scott Beeton, and Ted Pandaleon
Flow separation control using vortex generators on an inverted wing in ground effect is experimentally investigated, and its performance is characterized in terms of forces and pressure distributions over a range of incidence and ride height. Counter-rotating and co-rotating rectangular-vane type vo ... [J. Fluids Eng. 131, 121102 (2009)] published Thu Nov 19, 2009.
Autonomous microfluidic transport using electrowetting-based valves and integrated cells
Papaorn Siribunbandal, Shigeki Yamaguchi, Kenichi Kojima, Junji Fukuda, and Hiroaki Suzuki
Autonomous control of the transport of solutions in microfabricated flow channels using electrowetting-based valves and integrated electrochemical cells is proposed. An electrowetting-based valve formed with a gold electrode was opened when an electrolyte solution reached a zinc electrode in a contr ... [Appl. Phys. Lett. 95, 204105 (2009)] published Thu Nov 19, 2009.
Electrohydrodynamic repulsion of droplets falling on an insulating substrate in an electric field
Bumjoo Kim, Intae Kim, Sang W. Joo, and Geunbae Lim
Control technique for charged droplets, named as electrohydrodynamic droplet repulsion (EDR), is reported. Charged droplets emitting from a capillary and falling down toward an insulating substrate are deflected from their intended impact point due to the like polarity of previously fallen droplets. ... [Appl. Phys. Lett. 95, 204106 (2009)] published Thu Nov 19, 2009.
Flows around Confined Bubbles and Their Importance in Triggering Pinch-Off
Volkert van Steijn, Chris R. Kleijn, and Michiel T. Kreutzer
We describe the breakup of a confined gas thread in a cross-flowing stream of liquid at capillary numbers Ca<10. The breakup is initiated, not by a Plateau-Rayleigh instability, but by liquid that flows from the tip of the thread to the neck where pinch-off occurs. This flow, faster than previously ... [Phys. Rev. Lett. 103, 214501 (2009)] published Thu Nov 19, 2009.
Destabilizing effect of density gradient on the KelvinHelmholtz instability
L. F. Wang, C. Xue, W. H. Ye, and Y. J. Li
In this paper, we derive explicit analytic formulas for the linear growth rate and frequency of the KelvinHelmholtz instability in fluids with the density gradient. The analytic formulas are in excellent agreement with the results of two-dimensional numerical simulation. We found that the density gr ... [Phys. Plasmas 16, 112104 (2009)] published Wed Nov 18, 2009.
Inertial range scaling of the scalar flux spectrum in two-dimensional turbulence
W. J. T. Bos, B. Kadoch, K. Schneider, and J.-P. Bertoglio
Two-dimensional statistically stationary isotropic turbulence with an imposed uniform scalar gradient is investigated. Dimensional arguments are presented to predict the inertial range scaling of the turbulent scalar flux spectrum in both the inverse cascade range and the enstrophy cascade range for ... [Phys. Fluids 21, 115105 (2009)] published Wed Nov 18, 2009.
Continuous spectrum analysis of roughness-induced transient growth
N. A. Denissen and E. B. White
Continuous spectrum amplitude distributions are calculated for transiently growing roughness-induced perturbations in a flat-plate boundary layer. A direct method is employed when the complete flow is known via direct numerical simulation. A new method using regularizing functionals is developed for ... [Phys. Fluids 21, 114105 (2009)] published Wed Nov 18, 2009.
Comment on Heat transfer in vacuum packaged microelectromechanical system devices [Phys. Fluids 20, 017103 (2008)]
Yoshio Sone
It is pointed out that the solution of a free molecular gas in a bounded domain proposed as speculation in Sec. II of Cai [Phys. Fluids 20, 017103 (2008)] and in Sec. II of Cai and Liu [Phys. Fluids 20, 067105 (2008)] and its result of the vanishing of flow velocity were rigorously derived under a m ... [Phys. Fluids 21, 119101 (2009)] published Wed Nov 18, 2009.
Reconnecting flux-rope dynamo
Andrew W. Baggaley, Carlo F. Barenghi, Anvar Shukurov, and Kandaswamy Subramanian
We develop a model of the fluctuation dynamo in which the magnetic field is confined to thin flux ropes advected by a multiscale model of turbulence. Magnetic dissipation occurs only via reconnection of the flux ropes. This model can be viewed as an implementation of the asymptotic limit R-->[infini ... [Phys. Rev. E 80, 055301 (2009)] published Wed Nov 18, 2009.
Preparation of monodisperse emulsions by hydrodynamic size fractionation
Linas Mazutis and Andrew D. Griffiths
We describe a microfluidic system allowing fast and efficient size-dependent separation of droplets using hydrodynamics. This system allows efficient fractionation of droplets with a difference in volume as small as 2.33-fold (corresponding to a 1.33-fold difference in diameter of spherical droplets ... [Appl. Phys. Lett. 95, 204103 (2009)] published Wed Nov 18, 2009.
Clebsch parameterization: Basic properties and remarks on its applications
Z. Yoshida
The Clebsch parameterization (u=[del][cursive phi]+alpha[del]beta) has advantages in elucidating structural properties of vector fields; for example, it helps formulating the Hamiltonian form of ideal fluid mechanics, representing topological constraints (Casimir invariants), integrating the Cauchy ... [J. Math. Phys. 50, 113101 (2009)] published Wed Nov 18, 2009.
Effect on Radiant Heat Transfer at the Surface of a Pool Fire Interacting With a Water Mist
J. P. Garo, J. P. Vantelon, and D. Lemonnier
It is well established that the use of water mist can be an attractive alternative to gaseous suppression agents to extinguish fires for specific scenarios. Among the main mechanisms, which act together to extinguish fires when using a water mist: heat extraction, oxygen displacement, and radiant he ... [J. Heat Transfer 132, 021007 (2009)] published Wed Nov 18, 2009.
Fixed Grid Simulation of Radiation-Conduction Dominated Solidification Process
Piotr Lapka and Piotr Furmanski
In this paper conduction-radiation controlled solidification process of semitransparent materials was numerically analyzed. New approach in this kind of simulations, which is based on the fixed grid front tracking method combined with the immersed boundary technique, was adopted and examined. The pr ... [J. Heat Transfer 132, 021009 (2009)] published Wed Nov 18, 2009.
A Numerical Simulation of Combined Radiation and Natural Convection in a Differential Heated Cubic Cavity
P. Kumar and V. Eswaran
This article presents a numerical simulation of combined radiation and natural convection in a three-dimensional differentially heated rectangular cavity with two opposite side walls kept at a temperature ratio T/T=2.0 and T=500 K, with others walls insulated. A non-Boussinesq variable density appr ... [J. Heat Transfer 132, 021006 (2009)] published Wed Nov 18, 2009.
Scaling and correlation of vorticity fluctuations in turbulent channels
Ronald L. Panton
Data from direct numerical simulations have been correlated to examine the effects of Reynolds number on vorticity fluctuation profiles. Three different scalings are found: two in the inner region and the third in the outer region. In the inner region a two-term asymptotic expansion is required to r ... [Phys. Fluids 21, 115104 (2009)] published Tue Nov 17, 2009.
Periodic response of fluidic networks with passive deformable features
Matthew R. Begley, Marcel Utz, Daniel C. Leslie, Hossein Haj-Hariri, James Landers et al.
This paper outlines the scaling parameters governing the frequency response of fluidic networks with embedded deformable features, which are subjected to periodic excitation. These parameters describe the impact of deformable feature properties on the relative importance of potential energy, kinetic ... [Appl. Phys. Lett. 95, 203501 (2009)] published Mon Nov 16, 2009.
Shock tube experiments and numerical simulation of the single-mode, three-dimensional RichtmyerMeshkov instability
C. C. Long, V. V. Krivets, J. A. Greenough, and J. W. Jacobs
A vertical shock tube is used to perform experiments in which an interface is formed using opposed flows of air and SF. A three-dimensional single-mode perturbation is created by the periodic vertical motion of the gases within the shock tube. RichtmyerMeshkov instability is produced by an impulsive ... [Phys. Fluids 21, 114104 (2009)] published Mon Nov 16, 2009.
Spectrum of a passive scalar in moderate Reynolds number homogeneous isotropic turbulence
L. Danaila and R. A. Antonia
For moderate Reynolds numbers, the spectral scaling exponents of both velocity [E(k)[proportional]k] and the transported passive scalar [E(k)[proportional]k] fields exhibit departures from the asymptotic prediction m=m=5/3. However, at the same Reynolds number, the passive scalar spectrum for homoge ... [Phys. Fluids 21, 111702 (2009)] published Mon Nov 16, 2009.
Absence of Marangoni convection at Marangoni numbers above 27,000 during water evaporation
Ian Thompson, Fei Duan, and C. A. Ward
Two mechanisms by which Marangoni convection can be produced at the interface of water with its vapor are: (1) by imposing a temperature gradient parallel to the water-vapor interface, and (2) by imposing a temperature gradient perpendicular to the interface that results in the liquid becoming unsta ... [Phys. Rev. E 80, 056308 (2009)] published Mon Nov 16, 2009.
Pattern formation and interface pinch-off in rotating Hele-Shaw flows: A phase-field approach
R. Folch, E. Alvarez-Lacalle, J. Ortin, and J. Casademunt
Viscous fingering dynamics driven by centrifugal forcing is studied for arbitrary viscosity contrast. Theoretical methods, including exact solutions, and numerics based on a phase-field approach are used. Both confirm that pinch-off singularities in patterns originated from the centrifugally driven ... [Phys. Rev. E 80, 056305 (2009)] published Mon Nov 16, 2009.
Pinch-off singularities in rotating Hele-Shaw flows at high viscosity contrast
E. Alvarez-Lacalle, J. Casademunt, and J. Eggers
We study the evolution of a family of dumbbell-shaped liquid patches surrounded by air inside a rotating Hele-Shaw cell with lubrication methods and numerical simulations. Depending on initial conditions, the dumbbell either stretches to infinity, pinches off at the neck to form a droplet, or collec ... [Phys. Rev. E 80, 056306 (2009)] published Mon Nov 16, 2009.
Lagrangian transport induced by peristaltic pumping in a closed channel
Chiu-On Ng and Ye Ma
Lagrangian transport induced by peristaltic waves traveling on the boundaries of a two-dimensional rectangular closed channel is studied analytically. Based on the Lagrangian description, an asymptotic analysis is performed to generate explicit expressions for the leading-order oscillatory as well a ... [Phys. Rev. E 80, 056307 (2009)] published Mon Nov 16, 2009.
Statistical mechanical theory for nonequilibrium systems. X. Nonequilibrium phase transitions
Phil Attard
A general theory for the stability and coexistence of nonequilibrium phases is formulated. An integral formulation of the second entropy is given, the functional maximization of which yields nonlinear hydrodynamics. RayleighBenard convection is analyzed, and analytic approximations are obtained for ... [J. Chem. Phys. 131, 184509 (2009)] published Fri Nov 13, 2009.
Time-resolved proper orthogonal decomposition of liquid jet dynamics
Marco Arienti and Marios C. Soteriou
New insight into the mechanism of liquid jet in crossflow atomization is provided by an analysis technique based on proper orthogonal decomposition and spectral analysis. Data are provided in the form of high-speed videos of the jet near field from experiments over a broad range of injection conditi ... [Phys. Fluids 21, 112104 (2009)] published Fri Nov 13, 2009.
Localized edge states in plane Couette flow
Yohann Duguet, Philipp Schlatter, and Dan S. Henningson
The dynamics at the threshold of transition in plane Couette flow is investigated numerically in a large spatial domain for a certain type of localized initial perturbation, for Re between 350 and 1000. The corresponding edge state is an unsteady spotlike structure, localized in both streamwise and ... [Phys. Fluids 21, 111701 (2009)] published Fri Nov 13, 2009.
Diffuse-Charge Effects on the Transient Response of Electrochemical Cells. (arXiv:0910.5357v2 [physics.chem-ph] UPDATED)
ePrint arXiv http://arXiv.org/
Slow dynamics of phospholipid monolayers at the air/water interface. (arXiv:0910.3280v2 [physics.flu-dyn] UPDATED)
ePrint arXiv http://arXiv.org/
Orientation control of rodlike objects by flow. (arXiv:0905.0091v3 [physics.flu-dyn] UPDATED)
ePrint arXiv http://arXiv.org/