The Effects of Humidity on the Properties of Air and the Influence of Condensation on the Pressure Distribution over an Aerofoil

Changes in gas properties due to humidity are calculated for a range of atmospheric conditions. A simple Rayleigh flow model is also developed to assess latent heat exchange (condensation) effects in transonic flows and good agreement is obtained with published calculations for a CAST-10 aerofoil using a modified Euler code. The Rayleigh method is used to demonstrate the potential for significant condensation effects in flight under recorded humidity levels, although property changes are generally too small to have a significant effect.