Modified Diffusion Model of Pseudo-Shock Waves Considering Upstream Boundary Layers

Abstract

Up to the present, two flow models for pseudo-shock waves have been presented, i.e. shockless model and diffusion model. However, since the effects of upstream boundary layer and wall friction in the pseudo-shock region are not considered in these models, the flow properties calculated by these models are identical with those by the theory of normal shock wave, and they are much different form experimental values. In the present study experiments have been performed to investigate the effects of the upstream boundary layer on the pseudo-shock waves, by varying the Mach number and boundary layer thickness upstream of the pseudo-shock. Based on the results and modifying the diffusion model, a new flow model of the pseudo-shock has been presented in which both effects of the upstream boundary layer and the wall friction are taken into account. Calculated values by this modified diffusion model agree better with the experimental values than the previous flow models.