A method for the measurement of mixing properties in a turbulent jet flow

An experimental investigation of the flow development of a turbulent air jet of circular cross section exhausting into still air was carried out in order to test a method for measuring certain parameters relevant to the mixing process. The measurement method involves laser equipment in combination with the introduction of a tracer in the jet in the form of oil smoke. The flow field was examined at locations varying from two to twenty diameters downstream of the nozzle. A laser doppler velocimeter and a laser scatter system were used to measure flow velocity and tracer concentration. Main parameters recorded at each downstream station were mean axial velocity, mean concentration, fluctuating velocity and concentration, and velocity-concentration correlation. Results show that the method permits an accurate description of the nozzle fluid concentration and velocity fields for a round turbulent free jet. Measurements are in general agreement with data from other sources.