Large-eddy simulation of shock-wave/boundary-layer interaction control using a backward facing step

A new passive flow control method, putting a backward facing step ahead of the shock interaction position, is numerically investigated, aiming to control the shock-wave/boundary-layer interaction in a rocket-based combined-cycle scramjet engine. The height of the step is designed to be smaller than the boundary layer thickness. Implicit large-eddy simulations of an oblique shock wave impinging on a supersonic turbulent boundary layer are performed to examine the efficiency of this flow control method. Results show that with the flow control the length of shock-induced separation bubble is increased, but its height is reduced. The upstream extending of the reflected shock is suppressed, which indicates that the flow control method is able to relieve or avoid the adverse effects caused by the inner going of the reflected shock into the air-intake of the engine. The mechanism and the influence of the applied control method on instantaneous, mean and statistical flow-fields are discussed. (C) 2018 Elsevier Masson SAS. All rights reserved.