振荡叶栅粘性非定常绕流计算的双时间法

Application of Dual-Time Stepping Method to Calculating Unsteady Viscous Flow around Oscillating Cascade

通过求解雷诺平均 Navier- Stokes方程 ,借助运动网格技术 ,进行了二维振荡叶栅粘性绕流的数值模拟。成功地引入了双时间方法来处理这种振动物体的非定常流动问题 ,在确保时间 /空间精度的前提下 ,大大加速了计算过程。在双时间法的虚拟时域推进中 ,采用了高效的多重网格技术 ,使得双时间法的优势得以充分发挥。所给出的几种二维振荡叶栅非定常绕流的算例 。

Aeroengine blades often fracture under flutter or forced vibration. The calculation of unsteady viscous flow around oscillating cascade is useful in predicting the behavior of aeroengine blades under flutter or forced vibration, but such computations are very burdensome. We propose to greatly reduce the amount of computation by applying the Jameson's dual-time stepping method. We used a second-order accuracy finite volume method for spatial discretization and the four-stage Runge-Kutta scheme for time marching. The Jameson's dual-time stepping method allows the conversion of an unsteady flow problem in real-time region into a steady flow problem in pseudo-time region, thus permitting the mature tools in accelerating the computation in steady flow problems - the multigrid, local time step and the implicit residual smoothing - to be used in calculating unsteady viscous flow around oscillating cascade. We give two numerical examples. The computed results are in good agreement with published data. It is shown that the amount of computation can be reduced by 85%-90%.