Pre-compression flow on fore-body of space-plane at mach 10

Pre-compression on a fore-body of a space-plane with air-breathing engines is effective on an improvement of the propulsion performance at super/hypersonic speeds. On the other hand, the inlet distortion that is caused by flow expansion at the vicinity of the fore-body side-edge and boundary layer growth can cancel the pre-compression effect on the propulsion performance. In the present investigation, pre-compression flow on the fore-body of the space-plane at a Mach number of 10 was experimentally investigated at the NAL's hypersonic wind tunnel. The test results show that longitudinal vortices due to inboard pressure gradient in the spanwise direction could occur along the center-line of the lower surface of the fore-body in spite of the windward side. The vortices could cause serious pressure loss at the engine inlet location. In the vicinity of the side-edge of the fore-body, also, the flow distortion at the engine inlet location could be observed due to flow spillage(i.e. flow expansion).