Interaction of Shocks and Vortices in a Highly Underexpanded Supersonic Impinging Jet

A large eddy simulation of a highly underexpanded supersonic jet impinging on a large plate is reported. The Favre filtered compressible Navier-Stokes equations in cylindrical coordinates have been solved by using a finite difference method. The large eddy simulation code employs a fifth-order weighted essentially nonoscillatory scheme known as WENO for the convective fluxes, a fourth-order centered difference approach for the viscous fluxes, and a four-stage third-order strong-stability-preserving Runge-Kutta technique in time. The numerical simulation successfully captures the shock wave structure in the jet plume and vortex structures with different scales in the inner and outer shear layers. The evolution of annular shock waves and the vortex in the inner shear layer has been observed. Under the impact of the inner and outer shear layers, the interlacing vortex structures in the wall jet are formed. From this simulation, it can be concluded that the generation and disappearance of the annular shock arise from the actions of the Mach disk, the oblique shock wave, vortices in the inner shear layer, and the impinging plate, all combined.