Investigation of Shock Wave Induced Flow Separation over a Flexible Panel in Supersonic Flows

摘要

The fluid structure interaction generated by an oblique shock wave impinging on a flat flexible panel has been investigated experimentally. The imaging shock was generated by a shock generator with a ramp angle of 8° and freestream Mach number was set at 2.5. The pressure differential across the panel thickness was controlled with excellent precision by adjusting the cavity pressure beneath the panel to traverse a wide range of interesting pressure conditions that result in different panel deflection contours. In this study the two candidate pressure differentials are investigated - cavity pressure of 1 atmosphere that resulted in a convex curvature, and cavity pressure matching the freesream static pressure that resulted in concave curvature due to shock loading. Multiple surface and off-body diagnostics were implemented to obtain a deeper understanding of the global flow feature modifications that occur with convex and concave curvatures. The panel deflection contours computed using a Rayleigh-Ritz numerical approach suggest a maximum deflection of 1 mm and 3 mm for the concave and convex curvature configurations, respectively. Surface streakline visualization showed that the resulting shock strength was not sufficient enough to cause a boundary layer flow separation on a rigid flat plate. However, in the case of the flexible panel, the oblique shock was seen to have caused a local flow separation when a concave curvature was introduced. The wall pressure field measured on the concave panel revealed an initial acceleration of the flow before it encounters the oblique shock.