Impact of rotation change on the emptying of an ideal bottle of water
Abstract
We are carrying out the experimental study of the emptying of a hermetically sealed cylindrical tank in a rotating frame. We determine the optimal rotational velocity for the tank, which minimizes the emptying time. Moreover, there exists a critical rotation velocity at which the emptying time exceeds that of the nonrotating case, depending on the relative duration of each of the three emptying regimes identified in this flow, namely, (i) a bubble regime, (ii) a vortical air jet regime, and (iii) a bathtub vortex regime. The three regimes, easily distinguished by the shape of the air-water interface, have different draining velocities. The lifetime of each regime, as well as the transitions between them, depend on both the water level and the rotating velocity of the platform.