A note on entrainment in turbulent jets and plumes

Theories on the behavior of turbulent buoyant jets and plumes are generally based on the balance laws of mass momentum and heat and are closed with an assumption regarding the entrainment rate. This closure condition has been recently replaced by the kinetic energy equation but such a closure condition only allows workers to accurately match the pure jet experiments. Using a generalized moment of the momentum equation, it is shown in this paper that a smooth transition is provided between the pure jet and pure plume behavior which allows matching with both pure jet and pure plume behavior.