TY - GEN
T1 - Simulation of near continuum, hypersonic flow using a modular particle-continuum method
AU - Desehenes, Timothy R.
AU - Boyd, Iain D.
AU - Schwartzentruber, Thomas E.
PY - 2009
Y1 - 2009
N2 - A modular particle-continuum (MPC) method is used to simulate a low Knudsen number, steady-state hypersonic flow which exhibit small regions of collisional nonequilibrium within a mainly continuum flow field. This method loosely couples an existing direct simulation Monte Carlo (DSMC) code to a Navier-Stokes solver (CFD) while allowing both time-step and cell size to be completely decoupled between each method. Full thermal nonequilibrium (rotational and vibrational) is implemented in both flow modules with compatible relaxation models. The goal of the present investigation is to study the effect of locally rarefied regions on the heat transfer along the after body of a planetary probe body. Previous research suggests that poor agreement in after body heating could be due to locally rarefied regions along the rear surface of blunt bodies in hypersonic flow. Hybrid simulations are compared to full CFD and experimental measurements for high density, hypersonic flow over a sting-mounted planetary probe configuration. By using a hybrid method, the effect of rarefied regions can be examined for a very low Knudsen number case where the computational expense of performing full DSMC calculations is very high due to the four order of magnitude variation in characteristic length and time scales and unnecessary due to the large continuum region. Despite an increase in physical accuracy in the wake region, the initial MPC results have the same level of agreement with experimental measurements as the full CFD solutions. This could be due to insufficient transient time for the MPC simulation and will be explored in the future.
AB - A modular particle-continuum (MPC) method is used to simulate a low Knudsen number, steady-state hypersonic flow which exhibit small regions of collisional nonequilibrium within a mainly continuum flow field. This method loosely couples an existing direct simulation Monte Carlo (DSMC) code to a Navier-Stokes solver (CFD) while allowing both time-step and cell size to be completely decoupled between each method. Full thermal nonequilibrium (rotational and vibrational) is implemented in both flow modules with compatible relaxation models. The goal of the present investigation is to study the effect of locally rarefied regions on the heat transfer along the after body of a planetary probe body. Previous research suggests that poor agreement in after body heating could be due to locally rarefied regions along the rear surface of blunt bodies in hypersonic flow. Hybrid simulations are compared to full CFD and experimental measurements for high density, hypersonic flow over a sting-mounted planetary probe configuration. By using a hybrid method, the effect of rarefied regions can be examined for a very low Knudsen number case where the computational expense of performing full DSMC calculations is very high due to the four order of magnitude variation in characteristic length and time scales and unnecessary due to the large continuum region. Despite an increase in physical accuracy in the wake region, the initial MPC results have the same level of agreement with experimental measurements as the full CFD solutions. This could be due to insufficient transient time for the MPC simulation and will be explored in the future.
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M3 - Conference contribution
AN - SCOPUS:77958554555
SN - 9781563479755
T3 - 41st AIAA Thermophysics Conference
BT - 41st AIAA Thermophysics Conference
T2 - 41st AIAA Thermophysics Conference
Y2 - 22 June 2009 through 25 June 2009
ER -