The Effect of a Simple Throat Distortion on the Downstream Flow in a Hypersonic Wind Tunnel Nozzle

Abstract

An experimental investigation was conducted in the GALCIT 2 1/2" Supersonic Wind Tunnel to determine the effect of a known distortion of the throat section of a hyper sonic nozzle on the flow in the region downstream from the throat. The flow in the nozzle with a rectangular throat section was compared with the flow in the same nozzle with the throat region distorted to produce a throat height which varied linearly across the throat section. The flow was investigated by means of Pitot pressure surveys in the horizontal plane of symmetry of the undistorted nozzle. The magnitude of the effect produced by the throat distortion was observed to be approximately that predicted by one-dimensional isentropic flow relations. However, the sign of the effect was reversed in about the distance required for a curved Mach line to cross the channel.