A developing boundary layer over an evaporating surface

The problem of air flow over a sudden change in surface temperature and humidity has been solved using mixing-length theory. The method is similar to that used by P. A. Taylor (1970) with some modifications. The form of the mixing length suggested by Blackadar is used and this allows calculation farther downwind. A vapor diffusion equation is included in the set of conservation equations and a vapor buoyancy term is included in the stability length. The vapor buoyancy is found to enhance significantly the turbulent diffusion but to a lesser degree than does the thermal buoyancy.