Hot-wire measurements of instability waves on sharp and blunt cones at Mach 6.

摘要

Calibrated hot wires were used in the Mach-6 tunnel to obtain mass-flux profiles and to study the amplitude and growth of instability waves on 7° half-angle sharp and blunt cones. Measurements were taken at several stagnation pressures (45, 70, 90, and 125 psia) on each of the cones. The boundary layer on the sharp cone was slightly thinner than that on the blunt cone. The measurements were compared to Navier-Stokes computations and linear stability analyses. These comparisons show good agreement in both the shape of the mass flux profiles and the value of the mass flux at the edge of the boundary layer. The frequency of the second-mode instabilities also agreed to within 8% at various pressures. The amplitude of the instabilities was seen to increase, and the frequency decrease, as distance from the nosetip was increased. The amplitude of the instabilities measured on the sharp cone were greater than those measured on the blunt cone.