Pumping by Beating on a Tube

Beating on an open elastic tube which has been bent into a U-form leads to a pumping effect, probably related to the so called Liebau effect. This pumping can be appreciable, a water head of 50cm or more being easily manually attainable. For low frequencies no pumping occurs. For higher frequencies pumping may take place in both directions, dependent on the beating, tube and fluid characteristics. The pumping effect generally reaches a maximum for percussion positions distant from the mid-point between the ends of the tube and is generally in the direction of the longer length of the tube. The dynamics of this system in these experiments calls certain of the many prevalent theories on this mechanism into question.© 2002 ASME