Incipient separation on flared bodies at hypersonic speeds

The aerodynamic effectiveness of a cylinder-flare body at zero incidence un der laminar and turbulent boundary-layer conditions has been studied experi mentally. Two nose geometries, namely a 10 degrees half-angle sharp cone an d a hemisphere, were used. The study has been carried out in a hypersonic g un tunnel at a Mach number of 8.2 and a Reynolds number of 158,100, based o n the cylinder diameter, at flare angles 0 degrees, 10 degrees, 20 degrees, 30 degrees and 45 degrees. The surface flow was studied using oil-dot and liquid crystal techniques. Some information regarding the shock layer was o btained from schlieren pictures. The effects of entropy layer and boundary- layer state on flare effectiveness were deduced from pressure measurements over the cylinder and the flare.