计算可压缩边界层转捩及湍流的一种新方法——PSE+DNS

A New Method for Computing Laminar-Tubulent Trasition and Turbulence in Compressible Boundary Layers—PSE+DNS

提出了一种计算可压缩边界层转捩及湍流的新方法,它尤其适用于从小扰动开始的转捩及湍流计算.在层流阶段,直至转捩中的breakdown开始前,用抛物化稳定性方程(PSE)计算.然后用直接数值模拟(DNS)计算转捩过程和湍流,其入口条件是用PSE方法在该处得到的扰动.在两个测试算例中,包括亚音速和超音速边界层,此法得到的转捩位置和湍流都与只用DNS计算整个过程所得的一致.使用该方法的优点在于计算量比只用DNS方法小得多.

A new method for computing the laminar-turbulent transition and turbulence in compressible boundary layers was proposed. It is especially useful for the computation of laminar-turbulent transition and turbulence starting from small-amplitude disturbances. The laminar stage, up to the beginning of the breakdown in laminar-turbulent transition, was computed by parabolized stability equations （PSE）. Then the direct numerical simulations （DNS） method was employed to compute the transition process and turbulent flow, for which the inflow condition was provided by using the disturbances obtained by PSE method up to that stage. In the two test cases, including a subsonic and a supersonic boundary layer, the transition locations and the turbulent flow obtained by this method agree well with those obtained by using only DNS method for the whole process. The merit of using our method is that the computational cost is much smaller than that using only DNS method.