Synthesis on Test Case TC3 of ETMA Workshop

Abstract

The flat plate boundary layer is a classical wall flow against which any model of general use has to be validated. The primary character of the flow arises from the presence of the wall. Because of the no-slip condition, a low Reynolds number viscous layer is distinct from the high Reynolds number outer part of the boundary layer. This situation remains challenging for turbulence computations, since the asymptotic modelling of shear flows at high Reynolds number cannot be used everywhere in the flow. Similarly, in numerical methods, this flow requires large number of grid points to capture the small scales near the wall. The simple geometry relives us of all grid generation problems so that the physics of the models can be fully investigated. Furthermore, the case of boundary layers subjected to pressure gradients is very common in practice and has also to be examined. On the other hand, up to Mach number of 5, many aspects of supersonic boundary layer on adiabatic wall look very much the same as at low speeds, with variable density. A straightforward extension of the subsonic work can then be performed. The four sub-test cases are proposed and tested:

• TC3-1. Klebanoff’s zero pressure gradient boundary layer flow;

• TC3-2. Samuel & Joubert adverse pressure gradient flow;

• TC3-3. Spalart sink flow;

• TC3-4. Mabey’s supersonic flow on adiabatic wall (M = 4.5).