逆流矢量喷管流动自身导致的非定常现象

 基于数值方法，研究了逆流推力矢量喷管中由于流动自身导致的非定常现象。结果表明，当抽吸背压下降至某个范围时(50.66~60.8 kPa)，主流在接近外套壁面的某个位置处呈现出周期性振荡，流动参数(抽吸二次流量、推力矢量角、合成推力系数)也以小振幅振荡，但是同向二次流量却没有振荡。深入的流动机理分析表明，此时在逆流剪切层中，分离涡周期性地形成和发展，没有呈现出流动失稳，同时剪切层中的速度比又远大于定常流动下的值，因此流动表现为自激振荡特征。

Flow-induced Unsteady Phenomena in Counterflow Vectoring Nozzles

Unsteady phenomena induced in a counterflow vectoring thrust nozzle by the flow itself are studied by numerical simulation. The results show that when suction back pressure drops to a certain range (about 50.66-60.80 kPa), the main flow oscillates periodically at a location near the collar, and flow parameters (suction flow mass, vectoring angle and synthesis thrust coefficient) also oscillate periodically at a small amplitude, but the coflow keeps stable. This indicates that it is the counterflow shear lay...