Buoyant Forced-Plumes in Cross Flow

Buoyant forced-plumes in a neutrally stable cross flow were simulated in the laboratory flume. Saline solution was injected into the stream of fresh water to study the combined effects of exit-momentum flux and buoyancy. A simple theory based on dimensional argument and on the entrainment concept of Morton, Taylor, and Turner is proposed. It was found that the entrainment coefficient remains essentially constant (approx. 0.5) along the plume, independent of local density differences. The transition from near field, where flow depends on exit-momentum flux, to far field, where the effect of buoyancy dominates the flow, was found to occur at a downstream distance from the point of injection.