On the Unsteady Shock Wave Interaction with a Splitter Plate: Viscous Analysis

摘要

The present study examined the effects of viscosity and turbulence on the unsteady shock diffraction process over a splitter plate. It was found that the theoretical (in-viscid) wave patterns developed for the backward-facing step geometry are in fact formed in the viscous splitter plate flows; that is, viscosity did not affect the expected wave pattern. It is strongly recommended that further theoretical research be conducted to develop new wave patterns for branching ducts. The primary difference between the theory and simulations was the shape, structure, strength, speed, and number of the secondary shock, which was found to depend on time, M_s, A_2/A_1, viscosity, and turbulence. Regarding the unsteady shear layer, it was shown that adding viscosity (laminar) excites the instability (oscillates at a higher frequency than in the inviscid simulations) and adding turbulence damps out the instability (shear layer approaches a quasi-steady state over long periods of time). The shear layer and its instability were shown to interact strongly with the secondary shock. The long-term position and behavior of the shear layer were identified and the first quantitative measurements of the unsteady shear layer thickness are presented.