Influence of rotation and vibration on discharge of liquid from a cylindrical tank

Whenever vortex forms in a draining tank, it decreases the flow rate by reducing the effective cross sectional area of the drain outlet. Experiments show that the formation of the vortex and the draining time for the discharge of liquid from a cylindrical container depends on the flow disturbances present in it. In this paper the influence of rotation, and vibration in the vertical plane on the above phenomenon is investigated. The rotation imparted to the liquid in the tank is quantified and its influence on the critical height of vortex formation and time of draining is determined. Both the frequency and amplitude of vibration are systematically varied to study their influence on the phenomenon. Initial rotation is seen to augment vortex formation whereas the vibration tends to suppress the same.