ENTRAINMENT AND MIXING IN VERTICAL BUOYANT LIGHT-GAS PLUMES

A simple model is developed to determine the entrainment coefficient a nd the spread of a light-gas plume in a quiescent atmosphere. Experime nts performed with low-velocity saltwater/freshwater and helium-in-air jets indicate that buoyant gas plumes spread significantly faster tha n thermal plumes. The calculated effluent concentrations are in excell ent agreement with those measured when art entrainment coefficient of 0.15 is used in the plume equations. This is significantly higher than the entrainment coefficients of 0.075 to 0.093 reported for thermal p lumes.