A multiscale technique for the validation of a numerical code for predicting the pressure field induced by a high-power spark

A more precise knowledge of the pressure field induced by a high-power spark is essential to estimate the mechanical damage that a lightning strike can induce near the impact point. In this work we propose a multiscale approach to validate a numerical magnetohydro-dynamic model that can predict the pressure field when a very high-power discharge is considered. Two simplified models for the arc resistance are considered and their respective results are compared. A brief analysis regarding the numerical issues involved in the solution of a very high temperature gas is included. The numerical code has been validated against the experimental data of a short-arc discharge using a current waveform prescribed by the aeronautical standards. Our study shows that a strong shock wave is generated in the first power peak and this travels away from the arc column maintaining a relatively high strength a few tens of centimetres away. The pressure in the arc region remains high for the whole discharge period.