Numerical Simulation of Receptivity of Freestream Disturbances to Hypersonic Boundary Layers with Thermochemical Nonequilibrium
- University of California, Los Angeles
Laminar-turbulent boundary layer transition has been studied for more than a century since Reynolds’ experiments and is still poorly understood for hypersonic boundary layers. Nonlinear effects, real gas effects and receptivity processes are some of the topics that are still active areas of research. For studying hypersonic flows, inclusion of real gas effects is crucial for predicting flow parameters accurately. Real gas effects have recently been included in simulations and theoretical studies. Though there have been numerous research efforts since to simulate hypersonic flows with thermochemical nonequilibrium, there are limited numerical and theoretical studies on laminar-turbulent transition that have included thermochemical nonequilibrium. Real gas effects can radically change the receptivity process for the hypersonic boundary layer. Numerical study of unsteady flows requires high orders of accuracy to resolve vastly varying scales of space and time. Shock fitting methods can simulate hypersonic flow fields with high orders of accuracy throughout and even near the shock. Recently the authors developed a shock fitting method capable of simulating thermochemical nonequilibrium over a blunt body. This paper presents the numerical simulation of receptivity of hypersonic boundary layer with thermochemical nonequilibrium to free stream acoustic waves using the developed shock fitting algorithm. This is one of the first attempts at simulating receptivity of hypersonic boundary layer to free stream acoustic disturbances using shock fitting methodology and predicting second mode instability for real gas simulations. Test case for the current studies is based on free stream condition used earlier for experimental and numerical studies on double cone blunt bodies. Current studies predict that real gas effects destabilize the boundary layer. Real gas effects broadened the spectrum for unstable frequencies and lowered the most unstable frequency for the current case.
- Research Organization:
- Univ. of California, Los Angeles, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC02-06ER25797
- OSTI ID:
- 1107646
- Report Number(s):
- DOE/ER/25797-3
- Country of Publication:
- United States
- Language:
- English
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