An analysis of the axisymmetric turbulent buoyant jet

An analytical model is developed for a buoyant jet, i.e., the flow which forms when a fluid of one density is injected into an ambient fluid with a different density. Consideration is given to a fully developed, axisymmetric hot turbulent jet discharging vertically into a neutral environment. Equations for the conservation of momentum, temperature, and mass are defined in terms of the Boussinesq approximation. The momentum and temperature equations are integrated across the flow and initial conditions are defined for the momentum integral. A length scale of influence is defined in terms of the rates at which momentum and buoyancy are added. This 'forced' length scale describes the evolution of the buoyant jet and permits classifying regions of a pure jet and pure plume, as well as the transition region between the two.