Lightning-induced near-wall gas dynamic evolution and resultant wall loading on hypersonic aircraft structures

Hypersonic aircraft face severe lightning strike threats due to their poorly conductive thermal protection layers and inadequate lightning protection. These threats can lead to structural failure and mission loss. To investigate gasdynamic responses and potential mechanical damage mechanisms during lightning events, this study establishes a numerical framework for lightning channel simulation based on the Navier–Stokes equations. The model comprehensively integrates Joule heating, viscous radiation, short-wavelength thermal radiation, and electromagnetic effects under local thermodynamic equilibrium. Validation against experimental data confirms accurate prediction of lightning channel temperature, pressure, radius, and shock wave development. Analysis of near-wall processes reveals distinct thermal stratification within lightning channels. Viscous wall effects significantly alter near-wall morphology and thermodynamics but have a negligible influence on shock wave evolution, which closely matches the one-dimensional case. The wall sustains complex stress states featuring high-frequency oscillatory shear stress and high-magnitude normal pressure as primary mechanisms for material tearing and fracture. Therefore, spectral experiments should account for stratified structures; protection designs should extend beyond attachment zones due to impact risks on adjacent structures; high vibration frequencies call for attention to the integrity of high-stiffness components and the prevention of fastener loosening; high pressure significantly elevates the risk of fracture and tearing failure in brittle materials.