Aerodynamic performance simulation of hypersonic waverider in near space

Aerodynamic performance simulation software system of hypersonic waverider vehicles in near space was developed by using the direct simulation Monte Carlo (DSMC) method based on molecular dynamics. Taking a certain aerocraft as an example, the effectiveness of the system was verified. Aerodynamic performances of the vehicle at the height of 70-100 km in near space were simulated, the influence of rare gas effect on aerodynamic performance of the vehicle was studied. Collision model and effect collision number of the DSMC method were improved, in order to avoiding a large amount molecule collision calculation caused by DSMC simulation in continuous medium district and jumpiness district between temperature and velocity at the height of 70-100 km in the near space. The studied results show the characteristic of lift-to-drag ratio of the vehicle descends in near space, but it remains high lift-to-drag aerodynamic advantage; the difference of simulation results between the DSMC and NS equation increases with the height increasing and the effect of rare gas increases gradually; it is proved that fifteen effect collision number in every grid is enough to simulate the macrophysical characteristic of air in DSMC method.