Turbulent Penetrative Convection

This book deals with unsteady convection developing under the action of buoyancy source in a stably stratified fluid. A review of experimental data is presented, firstly from the laboratory, but also from meteorological and hydrological sources. A theoretical model is proposed based on the turbulent energy balance equation in the convective boundary layer, the similarity hypotheses for vertical profiles of turbulence characteristics, and the simplest representation of the energy flux carried by internal waves to the stratified layer. The theory gives a satisfactory explanation of practically all the published experimental data. As examples of environmental applications of the penetrative convection theory, problems are considered of the seasonal variations of temperature and bulk characteristics of turbulent mixing in a lake and of the convective growth of the atmospheric planetary boundary layer over land on a clear summer day or over a water basin over the period of nocturnal cooling. Finally a simple theoretical model of the thermal bar is presented.