High-fidelity Simulation of Oblique Detonation Waves
Sebastian Abisleiman, Ral Bielawski, Venkat Raman
Abstract
Oblique detonation waves are studied with high-fidelity simulations, including complex chemical kinetics for a hydrogen-air mixture at a stoichiometric equivalence ratio and 781 nm spatial resolution in the finest case, resulting in a minimum of 30 cells per induction length. In this analysis, the significant increase in oblique shock angle due to subsonic boundary layer interaction is shown to affect oblique detonation wave initiation through comparison of Zel'dovich-von Neumann-Doering (ZND) normalized ignition delay. Along the detonation surface, triple points are shown to have localized regions of high vorticity generation, leading to the appearance of Kelvin-Helmholtz instabilities, forming a shear layer. The overdriven detonation presents a cellular detonation structure on the surface that shows similarities to planar detonations through similar concave-convex flow features. Colliding transverse waves fuel this process and can be seen through normal and tangential velocities to the detonation surface. As shown through soot foil analysis, triple point instabilities can also oscillate in strength, coalesce, and form in time.