返回舱高雷诺数再入过程底部流动稳定性

返回舱高雷诺数再入过程中存在肩部高热流、底部阻力无法准确预测以及非定常振动等问题,解决此类问题的关键是分离和转捩等物理现象的准确识别.本文采用大涡模拟方法细致刻画了返回舱类钝体外形在高雷诺数再入过程中的分离和转捩等物理现象,获得了返回舱底部流动形态以及稳定性特征.从肩部剪切失稳、底部流动结构失稳、尾迹发展区以及远尾迹区...

BASE FLOW STABILITY OF RETURN CAPSULE DURING REENTRY PROCESS WITH HIGH REYNOLDS NUMBER

There are some problems of return capsule during reentry process, such as high heat flux of shoulder, prediction of base drag and unsteady vibration. Solve these problems, the key is accurate identification of separation and transition physical phenomenon. In this paper, separation and transition phenomenon of return capsule during reentry process under high Reynolds number condition are investigated by means of large eddy simulation (LES), base flow patterns and stability characteristics of return capsule are obtained. Physical mechanisms of base flow instability are analyzed from the aspects of shoulder shear instability, base flow structure instability and wake region instability. The results show that base flow stability of return capsule all includes shoulder shear instability mode and base flow structure instability mode, there is interaction between the two instability modes, there is are oscillation characteristics of Karman vortex street in the far wake turbulent region. These understandings support mechanism of the effect of external disturbances on the base region and stability control of return capsule in the theory.