超音速过流串联双空腔流场的DNS研究

Direct Numerical Simulation of Supersonic Flows over Two Tandem Cavities

本文采用直接模拟方法对超音速气流过流串联双空腔的流场进行研究,并与单空腔模型对照,分析了马赫数分别为1.5和2.5时双空腔之间的相互作用。结果显示空腔剪切层振荡对全场流动的控制作用,上游空腔对下游空腔中剪切层的运动有加强的趋势,它同时还可降低下游空腔壁面上的声压级;而下游空腔对上游空腔的影响则很微弱。串联双空腔产生的噪声辐射具有明显的方向性,其传播方向受马赫数的影响。

Supersonic turbulent flows over two tandem cavities are investigated by direct numerical simulation.For the purpose of comparison,a single cavity case is also included.The flows at Mach number 1.5 and 2.5 are calculated.The interactions between the two cavities are carefully studied.Results show that the cavity flows are basically dominated by the shear-layer oscillations.The upstream cavity can strengthen the shear-layer over the downstream cavity and reduce its sound pressure level on the walls.Contrarily,the impact of the downstream cavity on its upstream counterpart is weak.The sound waves generated by the cavities are directional.Their directions of propagation are affected by the Mach number.