Simulating lightning strikes to improve aircraft safety

When there is charge separation in air, lightning strikes equalize that separation and create high temperatures, pressures, and currents inside the lightning arc. Under certain conditions, these currents can damage material on metal and carbon fiber aircraft.

Previous work has explored the interaction between plasma and aircraft material during a lightning strike. Apsley et al. built upon these ideas with a radiative model.

“I worked on a critical part of the interaction, namely how you transfer the energy from the lightning arc to the aircraft substrate,” said author Miriam Apsley. “The radiative model allows you to work out how much energy the arc radiates outwards versus how much stays in the arc and gets passed on to your substrate, which is a key factor in determining how much damage is caused to the airplane material.”

The team adapted models that are often used for welding and considered the self-absorbed radiation in the lightning arc. They approximated the radiative transfer equation in increasingly complex ways, progressively including more information about geometry. This allowed the researchers to find accurate representations of the radiative processes without significantly increasing computational complexity.

The simulations agreed reasonably with experimental datasets and outperformed previous gray-body models, which do not account for the spectral dependency of absorbed radiation.

“We’re now working with Boeing on applied engineering aspects related to riveted substrate components,” said Apsley. “Rather than having to do several expensive lab experiments to evaluate and optimize new designs, you can make a first assessment on the computer, significantly reducing development costs.”

Source: “Equation of state driven radiative models for simulation of lightning strikes,” by M. Apsley, S. T. Millmore, and N. Nikiforakis, Physics of Fluids (2021). The article can be accessed at https://doi.org/10.1063/5.0074430 .