Reflects the growing practical applications for methods of computing the turbulent boundary layer based on relative limiting friction and heat exchange laws. Highlighted are conditions existing under two-phase flow and novel applications of injection critical parameters.

The expression for eddy diffusivity from a previous analysis was modified in order to account for the effect of kinematic viscosity in reducing the turbulence in the region close to a wall. By using the modified expression, good agreement was obtained between predicted and experimental results for heat and mass transfer at Prandtl and Schmidt numbers between 0.5 and 3000. The effects of length-to-diameter ratio and of variable viscosity were investigated for a wide range of Prandtl numbers.

An analysis of combined heat and mass transfer from a flat plate has been made in terms of Prandtl's simpified physical concept of the turbulent boundary layer. The results of the analysis show that tor conditioins of reasonably small heat and mass transfer, the ratio of the mass- and heat-transfer coefficients is dependent on the Reynolds number of the boundary layer, the Prandtl number of the medium of diffusion, and the Schmidt number of the diffusing fluid in the medium of diffusion. For the particular case of water evaporating into air, the ratio of mass-transfer coefficient to heat-transfer coefficient is found to be slightly greater than unity.