Abstract

Many important scientific and engineering applications, such as strong shock and turbulence interactions and hypersonic boundary-layer stability and transition, involve strong shocks and high temperature effects. These processes are strongly nonlinear and proven to be very complex to understand with existing tools. The most widely used shock capturing methods may incur numerical oscillations near the shock and may not be accurate enough for numerical simulations of hypersonic boundary-layer stability and transition problems. To solve such problems, a unique approach of using high-order shock-fitting method is adopted, where the shock is treated by shock-fitting method as a sharp boundary. However, there are no reported studies on the effects of transport coefficient modeling, chemical reaction rate and equilibrium constant modeling, internal energy mode modeling, and energy relaxation modeling. In this paper, the effect of transport coefficient modeling on hypersonic non-equilibrium flow simulations is considered using the recently developed high-order shock-fitting solver. The study is carried out by comparing numerical simulations with experimental datasets. The results consistently show that an increase of Lewis number leads to a decrease of shock standoff distance. For low and moderate enthalpy cases, different models of transport coefficient lead to minor change in shock standoff distance and flow field. Nevertheless, the pressure difference indicates that for pressure sensitive problems such as hypersonic boundary-layer stability and transition, one still needs to consider the effects of transport coefficient models.