Viscous-inviscid interacting flow theory

In this paper a viscous-inviscid interacting flow theory (IFT) is developed for an incompressible, two—dimensional laminar flow. IFT's main points are as follows. (1) By introducing a concept of interaction layer where the normal momentum exchange is dominating, a new three-layer structure is established. (2) Through the conventional manipulations and by introducing an interaction model, both the streamwise and normal length scales are proved to be functions of a single parameterm, which is related to the streamwise pressure gradient and Reynolds number. (3) The approximate equations governing the flow of each layer as well as the whole interaction flow are derived. The present IFT is applicable to both attached and attached-separation bubble—reattached flows. The classical boundary layer theory^[1] and Triple-deck theory^[2] are shown to be two special cases of the present theory underm=0 and 1/4, respectively. Furthermore IFT provides new distinctions of both the normal and streamwise length scales for flow-field numerical computation and also gives a new approach to developing the simplified Navier-Stokes (SNS) equations. The project is supported by the National Natural Science Foundation of China.