Measurement of kinematic parameters for a gas slug and estimate of bubble size

Slug velocity and length measurements are made from the acceleration and deceleration characteristics of a liquid film around a vertical gas slug. The unsteady disturbance is induced by the differential-pressure fluctuation which determines the length of the wake flow behind the slug. The probable size of the bubbles in the wake region is estimated through the amplitude spectrum of sound radiated from the trailing bubbles. No disturbance to the flow field is observed from the measuring instruments and the technique is not restricted to environment constraints.