Turbulent mass and momentum transport in round vertical turbulent buoyant jets

A two reference beam forward scattering laser-Doppler velocimeter and a laser induced fluorescence measuring device have been used to measure the velocity and concentration of a tracer in a round vertical buoyant jet discharging into an ambient fluid of uniform density. The two limiting cases, a jet (momentum driven flow) and a plume (buoyancy driven flow) are investigated systematically along with the transition from jets to plumes. The jet growth laws, velocity and concentration of a tracer decay are studied and constants of proportionality determined for the plume motion. The contribution of the turbulence to the mass transport of a tracer is examined for both jets and plumes and compared with prior estimates for plane buoyant jets.