Numerical Investigation of the Shear Layer Growth Influenced by Shock Waves in a Model Scramjet Engine

摘要

A numerical study has been conducted to investigate the effect of shock waves on the boundary layer growth and the mixing layer development in a model scramjet where a hydrogen jet is injected at 23 Ma into a Mach 2.0 surrouding air flow. The qualitative and quantitative agreements are found between the experimental data and the simulation results validating calculations are reasonable. The boundary layer thickness is carefullyed examined, which offers a renewed schematic of shock-wave/boundary-layer interaction featured with separation and reattachement. The thickness of the mixing layer is also calculated and plotted over the channel length to assess the impact of shock waves on its development. The mixing layer thickness increases wave-likely over the channel length as shock waves travel downstream and are reflected by the channel wall and the mixing layer. The mixing layer thickness decreases a little at the very location where the shock wave interacts with the mixing layer due to compression. Meanwhile, the induced vorticity makes contributions to the development of coherent structures in the mixing layer and leads to an increase of the mixing layer thickness.