Investigation of the Influence of Constant Adverse Pressure Gradients on Laminar Boundary-Layer Stability at Mach Number 8

Abstract : Measurements of fluctuating-flow and mean-flow parameters were made in the boundary layer on each of two axisymmetric, constant pressure gradient bodies in an investigation of the influence of adverse pressure gradients on the stability of a laminar boundary layer in hypersonic flow. Each test article was slender, constant pressure gradient flare combined with a sharp cone forebody with a 7-deg half angle. The test articles differed in the magnitude of the pressure gradient. The flow-fluctuation measurements were made using constant- current hot-wire anemometry techniques. Boundary-layer profiles and model surface conditions were measured to supplement the hot-wire data. Testing was done at Mach number 8 with a free-stream unit Reynolds number of 1.0-million per foot. The test equipment, test techniques, and the data acquisition and reduction procedures are described. The test was the ninth in a series of efforts which have investigated various aspects of hypersonic boundary-layer stability. (EDC)