The effect of humidity on laminar recovery temperature measurements in supersonic flow of air in wind tunnels

Abstract

Summary. Wind-tunnel tests have been made at a Mach number of 2.92 to measure the effect of humidity on laminar recovery temperature on a cone. Its effect is to increase the recovery temperature above that obtained with dry air. Consideration of the latent heat addition to the air in the condensation shock allows a theoretical estimate of recovery temperature to be made, based on true total temperature and true Mach number. The results agree with theory and support assumptions of no re-evaporation in the boundary layer and no change in recovery factor. An analysis of results published by Brun and Plan (M = 1.85) and Laufer and Marte (M = 4.02, 4.43, 4.71) is included. It is suggested that a device for the continuous measurement of laminar recovery temperature would provide a simple monitor of the degree of condensation in wind tunnels.