TEST FLOW PROPERTIES OBTAINED FROM VELOCITY, PRESSURE, AND PROBE MEASUREMENTS

摘要

Velocity-profile, pitot-pressure, and supplemental probe measurements have been made at the nozzle exit of an expansion tunnel (a modification of the Langley pilot model expansion tube) for a nozzle inlet condition of a nitrogen test sample with a velocity of 4.5 km/sec and a density 5 x 10-3 times the density of nitrogen at standard conditions, both with the nozzle initially immersed in a helium atmosphere and with the nozzle initially evacuated. The pur¬pose of this report is to present the results of these measurements and some of the physical properties of the nitrogen test sample which can be inferred from the measured results. The main conclusions reached are that:the velocity profiles differ for two nozzle conditions;regions of the flow field can be found where the velocity is uniform to within 5 percent and constant for several hundred microseconds;the velocity of the nitrogen test sample is reduced due to passage through the nozzle;and the velocity profiles do not significantly reflect the large variations which occur in the inferred density profiles.