DNS of strong shock and turbulence interactions with thermochemical non-equilibrium effects

Abstract

The underlying physics in shock and turbulence interaction is essential for a better understanding of many natural processes as well as scientific and engineering applications, such as volcanic eruption, supernova explosion, detonation, medical application of shock wave lithotripsy to break up kidney stones, and energy application of the implosion of a cryogenic fuel capsule for inertial confinement fusion. One of the fundamental building blocks in these complex processes and applications is the canonical problem of isotropic turbulence and a normal shock. Unfortunately, even this fundamental problem is not well understood for strong shocks. Recent direct numerical simulation (DNS) results of perfect gas flow showed some new trends in turbulent statistics as mean Mach number is increased. In this paper, we first conduct extensive DNS studies on canonical strong shock and turbulence interaction problem of perfect gas flow with mean Mach numbers ranging from 2 to 30. The results show that strong shock waves have a significant effect on turbulent statistics. However, gas temperature increases dramatically after strong shocks so that numerical simulations based on perfect gas flow may not be enough. The effects of thermochemical non-equilibrium flow including internal energy excitations, translation-vibration energy relaxation, and chemical reactions among different species need to be considered. We have developed a new high-order shock-fitting solver for non-equilibrium flow simulations based on the 5-species air chemistry and recently thermal non-equilibrium models. The code package has been tested and is being applied to DNS of strong shock and turbulence interactions with thermochemical non-equilibrium effects.