Exprimental Study of Spin-Up of a Fluid-Filled Cylindrical Tank

Abstract: To ensure safety on upper stage rockets, the fluid dynamic phenomenon known as sloshing in the liquid propellant tanks needs to be understood. CFD is a relatively cheap tool, but studies by Schmitt [7] suggest that models currently used for simulations do not predict the flow behavior.To verify computational models, experiments are setup on a cylindrical tank. The time for thefluid to become steady in a cylindrical tank rotating along the axis is measured for both a com-pletely water filled tank and a tank half-filled with water and half-filled with air. The method for measuring the time until steady state uses an open-source image-analysis tool based on Particle Image Velocimetry. The results for the air-water tank show no dependency on rotational speed or geometry of the tank. The results for the completely filled tank show spin-up times coherent with theoretical data for laminar Ekman layer boundary flow predicted by Sedney and Gerber [8] and show that the spin-up time is given by Es=8/√νΩ