A hybrid numerical scheme for aeroheating computation of hypersonic reentry vehicles

Hypersonic aeroheating simulations were conducted for three-dimensional (3D) reentry capsule for the Mars Science Laboratory (MSL) using the AUSM and the Roe schemes. The study confirms that AUSM family of schemes generate unphysical oscillations in the wall heat flux distributions due to the unstable simulation of the shock wave. And the wall heat flux is underpredicted by the Roe scheme due to excess dissipation, even though captures the shock wave accurately. In order to overcome these limitations, we develop a numerical scheme that can capture the shock wave stably and still maintain an accurate prediction of the heat flux. We propose a novel hybrid scheme that combines both the AUSM+ and Roe schemes. Two different hybrid techniques are proposed for switching between the two schemes, one based on the shock wave detection and other utilizing a criterion based on the distance from the wall. The implementation of the two hybrid schemes for the 3D MSL reentry capsule was studied for prediction accuracy compared to experimental data. It is found that the second hybrid scheme (based on the criterion for switching based on distance from the wall) can eliminate the unphysical oscillations in the wall heat flux distributions and improve the aeroheating prediction accuracy.