The Effect of the Condensation of Atmospheric Water Vapour on Total Head and Other Measurements in the N.P.L. High Speed Tunnels

摘要

A few observations indicated an increase in measured stagnation temperature commencing at the same Mach number as the pressure drop and caused by the heat released on condensation.nBecause of the higher local velocities, and therefore increased supersaturation, extensive condensation occurs near the surfaces of aerofoils at lower free-stream Mach numbers than it does in the free stream itself. This causes a drop in pitot reading in the wake and thus an increase in pitot traverse drag. It usually starts at Mach numbers near the critical and increases with speed.