Influence of base inclination on vortex formation during draining from cylindrical tanks

Abstract

When draining takes place from a cylindrical container, a vortex forms which can affect the rate of draining. This is because the vortex reduces the effective cross-sectional area of the drain port and thus decreasing the flow rate and increasing the time of draining. Experiments show that the presence of rotation augments the vortex formation which is basically due to the low pressure created at the bottom surface. The phenomenon can be expected to be influenced with changes near the base. In this paper the influence of base inclination on the vortex formation is systematically investigated. It is observed that the vortex is completely suppressed when the base inclination is above a limiting value which depends on the size of the drain port.