The p-DSMC modeling of radiation effect in three dimensional steady high enthalpy rarefied gas flow

The high temperatures within the shock layer of an extremely hypersonic flow led to the excitation of internal energy modes, accompanied by the emission of thermal radiation. However, simulation of three-dimensional hypersonic flows tightly coupled with radiation effects so far remains a significant challenge due to the complexity of the problem and the high computational cost, and most of the previously available numerical simulations on hypersonic flows coupled with the radiation effects are limited to one-dimensional or axisymmetric cases. To enhance the efficiency for simulating two dimensional hypersonic flows tightly coupled with radiation effects, an efficient p-DSMC method was proposed in our previous work. In this study, we mainly focus on the extension of the $p$-DSMC method to three-dimensional hypersonic flows with radiation effects. Furthermore, to validate the effectiveness of the $p$-DSMC method, the hypersonic flow with $\text{Ma}=40$ at the altitude $H=80$ km over the FIRE-II was simulated by the $p$-DSMC method and the conventional Navier–Stokes equation based CFD scheme, and a satisfying agreement of the wall radiation heat flux results, particularly in the vicinity of the stagnation point, computed by these two different methods can be observed, which indicates that the $p$-DSMC method can be a reliable tool for three-dimensional hypersonic flows with radiation effects. Additionally, the radiation effects for the FIRE-II flying with $\text{Ma}=41.24$ at the altitude $H=86$ km with different angles of attack and radius were numerically investigated with the $p$-DSMC method and the numerical results show that, as the angle of attack increases, the convective heat approaches the edge of the FIRE-II model and the location of the maximum radiative heat moves away from the center of the FIRE-II model, but remains close to the stagnation point.