Transport Phenomena in Thermally Stratified Boundary Layers

Abstract

Studies of heat, mass, and momentum transfer are made to analyze the formation of marine fogs in thermally stratified boundary layers in the atmosphere. The governing partial differential equations of continuity, momentum, temperature, and concentration are used to describe the transport phenomena. An additional equation of turbulence energy is introduced to account for the development of the turbulent motions. Simultaneous solution of this system of equations allows the turbulent exchange coefficients to be treated in the same way as all other dependent parameters. Verification of the theoretical approach is made by comparing the numerical predictions with wind tunnel simulations of neutral, stable, and unstable atmospheres. Application of the theory is extended to the investigation of the formation of advection fog over cold ocean surfaces. In addition to the established criteria obtained from wind tunnel data, the fog model takes into consideration the radiation and sedimentation of fog droplets as well as condensation and evaporation of liquid water.