Interactive boundary layer (IBL)

Abstract

We present here the Interacting Boundary Layer Equations. It is called Inviscid-Viscous Interactions as well. This is a way to solve an approximation of the Navier Stokes equations at large Reynolds number using the Ideal Fluid / Boundary Layer decomposition. But, instead of solving first the ideal Fluid and second the Boundary Layer, both are solved together. This “strong coupling” (or this Viscous-Inviscid Interaction) allows to compute separated flows. This was impossible in the classical Boundary Layer framework, because in this framework, the boundary layer is constrained by the Ideal Fluid which imposes its slip velocity at the wall. This coupling is justified in the Triple Deck theory which is the rational explanation of IBL. We present some numerical experiments showing some simple academic examples of interactions such as flows over bumps or wedges in subsonic, supersonic, subcritical and supercritical external flows and in pipes. Some examples from the literature are then presented.