Unifying failure: exploring the relationship between ejecta & spall

3D Large Eddy Simulation (LES) is used to explore the connections between ejecta and spall, in multiply shocked metal targets, having surfaces initially perturbed by periodic and non-periodic roughness profiles.

Surface jetting, due to shock-induced Richtmyer-Meshkov Instability at a perturbed surface [1,2], will be sensitive to material several wavelengths deep below the free surface. Once shocked, rarefactions travelling back into the bulk material can significantly affect the structure of this sub-surface region, causing variations in density, temperature, solid/melt phase, while also potentially causing breakup and cavitation due to spall. Subsequent re-shocks will be shaped by this new structure, leading to variations in local shock strength and breakout time that can enhance breakup and failure of the surface. In this work we explore the sensitivities of this complex failure process, using 3D LES applied to typical experimental conditions and assemblies.



[1] R. D. Richtmyer, Commun. Pure Appl. Math., 13:297 (1960).

[2] E. E. Meshkov, Fluid Dyn. 4:101 (1969)