Reduction of the separation bubble size using the pressure feedback channel in supersonic flow across a forward-facing step

In high-speed flow applications, increased aero-thermodynamic loads, localized turbulent regions, instability, excessive drag and pressure losses are among the negative effects of the interaction between shock waves and boundary layers and the subsequent separation of the boundary layer. These drawbacks emphasize how crucial it is to look into ways to control the boundary layer separation caused by shock waves. In order to determine whether using a pressure feedback technique to regulate boundary layer separation on a two-dimensional forward-facing step (FFS) is effective, a numerical study is conducted. The pressure feedback technique utilizes a channel to remove fluid from the separated area and reintroduce it into the mainstream flow, by leveraging the pressure contrast as the motivating factor. Ansys Fluent 2021 simulation software is used to conduct a numerical study investigating shock wave boundary layer interaction over a FFS at a supersonic Mach number of 2.5. The present study aims to explore the effectiveness of implementing a pressure feedback channel near the FFS as a strategy for controlling flow separation induced by the step. Turbulence effects are simulated using a k-omega model, and the study employs a finite-volume method with upwind flux difference splitting and second-order upwind flow discretization. The simulation results indicate the efficacy of the pressure feedback mechanism in reducing flow separation, thus enhancing its role in separation control. Integration of an 80mm channel results in a notable 42.85% decrease in separation bubble size, while the longer 90mm channel yields an even more substantial 52.38% reduction.