Free-Flight Base Pressure Measurements on 8 deg Cones

摘要

Base pressure measurements are presented on two 8 deg half angle, right circular cones with a tip bluntness ratio of 1%. Data are obtained at three radical base locations: r/R sub b = 0, r/R sub b = .5, and r/R sub b = .917. A unique free-flight technique was employed to obtain the data. The cones were launched nearly vertically from special guns and the data were telemetered to ground stations. The launch Mach numbers were approximately 3 with corresponding Reynolds numbers of 35 million. Both the Mach number and the Reynolds number decreased monotonically from their launch value reaching 400 and 250,000 respectively at apogee. In the laminar flow regime, the centerline base pressure is measured to be a few percent higher than either of the other two. At early times in the trajectory, where the boundary layer was expected to be turbulent, the opposite effect is noted.