二维非定常分离准则探讨

STUDY ON UNSTEADY SEPARATION CRITERION IN 2 D INCOMPRESSIBLE VISCOUS FLOW

利用奇点理论和连续方程证明，当坐标系与非定常分离点固结时，分离点应该是鞍型奇点。由此自然地导出了非定常分离准则。

Thanks to the need of the technical development the problem of separation in unsteady flow is attracting more and more attention. In fact, in the 50s of this century, the investigation of More, Root and Sears led to a model of unsteady separation, known as the MRS model.Up to now,there are a lot of criteria of the unsteady separation point,such as, null vorticity criterion, the criterion derived by Change.In this paper,it is proved that an unsteady separation point must be a saddle point and the criterion for the unsteady separation point is given based on the equation of instantaneous streamline and singular point theory.The method to locate a separation point in flow field is discussed.