INVESTIGATION ON THE ATTENUATION OF A ROTATING LIQUID MOTION IN A CYLINDER WITH BOUNDARY RESISTANCE

In order to study the attenuation process of a rotating liquid motion with boundary resistance, the laminar and turbulent flow friction models are used to calculate the head less, as well as a relative experiment is conducted to verify the mathematical approach. Based on equivalent wetted perimeter, a theoretical formula is established to calculate the energy loss due to wall resistance, in which the wall roughness, rotation radius, static water depth and rotation velocity are considered. Then, the attenuation of liquid rotating is measured in a circular cylinder, and the result agree with the theoretical model well. Based on the verified theoretical formula, the influences of various diameters and roughness coefficients on the attenuation are analyzed. The results show that the wall resistance and the cylinder size are the major factors to determine the attenuation process of the rotating liquid movement. The attenuation processes become more conspicuous with more roughness and less diameter.