Hypersonic drag reduction mechanism of a novel combinational spike and multi-opposing jets aerodynamic configuration

The shock wave drag significantly affects the aerodynamic performance of hypersonic vehicles, a novel combinational configuration is proposed to reduce the drag in this paper. The basic configurations are the spike, nose cone, front and rear jets, respectively. The numerical method is used to study the drag reduction performance. The combinational configuration has weaker reattachment shock wave than the other configurations, and both the peak pressure of nose cone and drag coefficient are decreased by more than 45%, which verifies the excellent drag reduction performance of combinational configuration. The influencing factors are analyzed in this paper. Lengthening the spike and increasing the total pressures of two jets can make the reattachment shock wave away from wall, weaken its intensity and increase the drag reduction performance. Furthermore, the change rates of wall pressure distribution of the nose cone and drag coefficient gradually decrease. When the sizes of two nozzles are small, the rear jet appears as the long penetration mode. When the sizes of two nozzles are larger than corresponding critical sizes, respectively, the rear jet will convert to the short penetration mode. Increasing the sizes of two nozzles makes the reattachment shock wave away from wall and increases drag reduction performance with the rear jet being SPM as well. The size and total pressure of front jet has greater influence on the drag coefficient. The influence of above factors on the flow characteristics and mass flow rate of nozzle is also studied in this paper.