S054032 Taylor-Proudman柱を伴った球の抗力係数([S054-03]噴流、後流およびはく離流れ現象の探求と技術革新(3))

Abstract

Experimental study was carried out on the flow created by a sphere moving along the axis of a rotating container filled with a viscous fluid. The measurements of the terminal velocity and angular velocity of a sphere, and the three-component velocity fields around the sphere were performed using a PIV system. Flow in a rotating system is governed by the Reynolds Re=w_<s∞>α/v, Taylor T=2Ωα^2/v and Rossby Ro=w_<s∞>/2Ωα numbers, where Ω is the angular velocity of the basic solid-body rotation, wsco and a are the sphere velocity and radius, respectively, and v is the kinematic viscosity. As predicted by the Taylor-Proudman theorem, the so-called Taylor-Proudman column is evaluated quantitatively. For low N (=1/Ro), the drag coefficient C_D is less than the value for N=0, and for large T and N, C_D becomes larger.