An experimental study of hypersonic wakes behind wedges at angle of attack

Experimental measurements of mean flow properties of hypersonic wakes behind wedges of 20° included angle were conducted for angles of attack up to 25° at Mach number 6, with Reynolds number based on wedge base height ranging from 7,000 to 55,000. The near and far wake structures were determined, including streamlines and velocity profiles, over a down-stream distance of 60 base heights. The base pressure is insensitive to incidence within about 17°. At higher incidence, flow separation occurs on the leeward surface. The near wake flow field changes accordingly. The far viscous wake (x/H > 4) changes with increasing incidence because of the increasing differences of the inviscid flow quantities at the leeward and windward edges of the viscous wake. The wake static pressure, which increases with incidence, viscous wake edge velocities, edge Mach number, edge temperatures and flow inclination of the real flow (directed towards the leeward side) compare favorably with a simple inviscid shock expansion model. In the laminar wake flows the wake widths, minimum velocities, minimum Mach numbers and maximum temperatures change little with incidence. However, in the transitional wake flows, the “break-away” phenomenon is observed and transition from laminar to turbulent flow moves upstream as angle of attach increases