Velocity measurements in a two-phase turbulent jet

The motion of oil droplets in a round turbulent air jet is investigated experimentally. Direct information on the droplets' average velocity is obtained by means of a Laser Doppler velocimeter. Average velocity profiles of the droplets are measured along the axis of the jet and transverse to it. The results are compared to the free jet expansion.The jet Reynolds number is in the range 10⁴–10⁵, the droplets' diameters are 50 μm and below and the volume concentration of the oil in the air is 10^?6.At the jet exit, the air velocity is higher than the droplets' velocity, at the developed region of the jet the droplets' velocity is found to be higher than the free air jet velocity at the same location. In the radial direction, the velocity profiles of the droplets are self similar and the droplets' velocity is lower than the free air jet velocity at the same location. The droplets' velocity decay along the axis of the jet is slower than the air velocity in the free jet and the two-phase jet is narrower than the submerged free air jet at the same exit velocity.