Flow Control of SBLI using Grooves with Suction

Abstract

Shock wave boundary layer interaction (SBLI) is often encountered in supersonic/hypersonic engine intakes and transonic flow over aerofoil. The interactionof ‘strong’ shockwith turbulent boundary layer can cause the reversal of flow velocity at bottom of thelayer. This flow reversalseparates the boundary layer from the wall, results in loss of thrust and engine efficiency.One among the proven method to control the flow separation due to SBLI is boundary layer mass suction.This paper discusses the control of SBLI through mass suction in different groove geometries. The ‘suction’ pressure applied at the bottom of the grooves effectively control flow separation and transforms the complex Type II shock-shock interference into a regular shock reflection. Static pressure rise across SBLI has been reduced to 50% of its peak value irrespective of groove shapes. A complete total pressure recovery has been achieved in ‘forward facing triangular’ case. A total pressure recovery up to 45% for ‘circular’ and 55% for ‘triangular’ has been attained. Among the geometries tested, ‘forward-facing triangular’ controls flow separation better than the other shapeswhereas the ‘forward facing blade’ controls the least. Reversal of flow velocity inside the gaps of ‘triangular’ grooves necessitate optimization of groove profile.

Keywords –SBLI, Intakes, Grooves, Shock waves