An Experimental Model for the Sharp Flat Plate in Rarefied Hvnersonic Flow

Abstract

Flowfield studies of the shock wave and boundary-layer development on a flat plate are presented for a region that bridges the gap between a classical hypersonic boundary downstream and a kinetic flow model at the leading edge. The measurements give a comprehensive picture of the flow pattern in the merged or layer regime, which exists upstream of the region of validity of hypersonic viscous interaction theory. The results are derived from a combination of several probing and optical techniques and surface pressure measurements. Previous models of slip flow or wedge-like flow were not supported. The shock wave was found to be quite different in thickness and structure from the classical picture of an oblique Rankine-Hugoniot shock, and these effects have not been treated adequately in existing theories. A true scale diagram of the flowfield is given which now makes it possible to evaluate more realistically the theoretical models that have been proposed.