An Experimental Investigation of Interactions betweenTaylor Column and Bathtub Vortex in Rotating Fluid

• Main Authors: Zi-Ya Li, 李孜亞
• Other Authors: 朱錦洲
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/28197346543630864582

碩士 === 國立臺灣大學 === 應用力學研究所 === 100 === The study is aimed to investigate interactions between a Taylor column and a bathtub vortex in a cylindrical rotating tank experimentally. The tank has a central drain-hole at the bottom boundary and a top-down cylinder which bring the Taylor column effect placed on the top boundary. We are interested in the case of prominent Taylor columns and Ekman layers, i.e., when both of Rossby number and Ekman number are much smaller then unity. We also examine the effect of the ratio of h/H and the effect of stacking several cylinders. It found that for the flow at geostrophic balance, the flow domain can be divided into three region: geostrophic bulk, Ekman layer and central vortex core. Moreover, there are formed five routes of exit flow patterns: (i) the fluid sneaks through the bottom Ekman layer and flows direct into the drain hole; (ii) the fluid sneaks through the bottom Ekman layer and subjects to Ekman pumping, and downwards to drain hole; (iii)the fluid moves up due to the Taylor column effect, a part of these sneaks through the bottom gap, then subjects to Ekman pumping, and downwards to drain hole; (iv)the fluid through the top Ekman layer and sneaks through the top gap to the dran-hole by downward central vortex core;(v) the fluid moves up due to the Taylor column effect, a part of these sneaks through the top gap, then follow the path(iv). Moreover, the effect of Taylor column depends on the height of cylinder. The position of the outer wall is confirmed by the experiment of stacking cylinder. The double eyewall is found obviously on the NP transition process.