High-Order Shock-Fitting Methods for Hypersonic Flow with Chemical and Thermal Nonequilibrium

Abstract

Computer simulations have been an effective tool to study transient flow processes in hypersonic flow and have been complementing experimental and theoretical studies to better understand the flow transition process. There have been lots of efforts in code development for high order simulation of nonequilibrium flow but most of the methods are based on shock capturing ideodology. Shock capturing schemes may not capture the flow processes with enough accuracy required to study flow transition. The essential requirements of such simulations are high order of accuracy of solutions in both space and time. We have developed a high order shock fitting code capable of simulating thermal and chemical nonequilibrium hypersonic flows. Shock fitting approach has the advantage of capturing the entire flow field with high order accuracy and without any oscillations near the shock which shock capturing schemes may exhibit for strong shocks. We have tested and validated the code thoroughly over a wide span of free stream conditions and geometries. We have implemented the current updated models available in literature for nonequilibrium and transport phenomenon. This code would be starting point for simulations to study real gas effects on receptivity for free stream disturbances and their transition to turbulence in the boundary layer, and for study of transition in ablative boundary layers. Here we present the methodology and validation cases for the code. The code in current form is up to third order accurate in time and fifth order accurate in space.