Three-Dimensional Normal Shock-Wave/Boundary-Layer Interaction in a Diffuser

The 3D flow structure induced by a normal shock-wave/boundary-layer interaction in a transonic diffuser is experimentally and computationally investigated. In the diffuser, the shock wave is located in the diverging section. The experiments are done with wall pressure measurements, oil-flow surface visualization, and Mach number measurements with a laser-induced fluorescence (LIF) method. In the computational work, the Reynolds-averaged Navier-Stokes equations are numerically solved with the k-omega two-equation turbulence model. The numerical solution agrees reasonably well with the experiment and clarifies the vortex structure in the interaction zone along with the 3D behavior of the boundary layer downstream of the shock wave. A careful investigation of the calculated flow reveals that the vortices are generated at the foot of the shock wave. It is also found that a complicated wave configuration is formed near the diffuser corner. A flow model is constructed by considering this wave configuration. This model explains the 3D flow characteristics in the transonic diffuser very well.