An experimental investigation of hypersonic flow over blunt nosed cones at a mach number of 5.8

Abstract

Six spherical nosed cone static pressure models with cone semivertex angles of 10°, 20°, and 40° were tested in the GALCIT 5 x 5 inch hypersonic wind tunnel at a Mach number of 5.8. The static pressure distributions obtained at yaw angles of 0°, 4°, and 8° agreed very closely with the modified Newtonian approximation, Cp = Cpmax cos2η on the spherical portions of the models, where η is the angle between the normal to the body surface and the free stream direction. On the conical portions of the models the pressure distributions agreed reasonably well with the theoretical results for inviscid supersonic flow over cones as tabulated by Kopal. The significant parameter which influenced the deviations from the Newtonian and the Kopal predictions was the cone semivertex angle. The flow over the 40° spherical nosed cone models overexpanded with respect to the Kopal pressure in the region of the spherical-conical juncture, after which the pressure returned rapidly to the Kopal value. For models with smaller cone angles the region of minimum pressure occurred farther back on the conical portion of the model, and the Kopal pressure was approached more gradually. The shape of the pressure distributions as described in nondimensional coordinates was independent of the radius of the spherical nose and of the Reynolds number over the range of Reynolds number per inch between . 97 x 105 and 2.38 x 105. Integrated results for the pressure foredrag of the models at zero yaw compared very closely with the predictions of the modified Newtonian approximation, except for models with large cone angles and small nose radii.