점度 가 相異한 流體境界面 근처 에서 圓柱주위 의 二次元 低速流動 의 解析

Slow Motion of a Circular Cylinder Near the Plane Interface of Viscous Fluids

When a circular cylinder near the plane fluid-interface of different viscosities is in parallel and normal motion, solutions of the Oseen equation are obtained. Classical image method with Faxen's integral form is used to satisfy the boundary conditions on the plane interface. Coefficients of drag and lift increase as a cylinder approaches to the interface. But drag-coefficients of parallel motions with viscosity-ratio less than unity are decreased slightly. They show monotonic increase with Reynolds number in case of parallel motion, but minimum values of drag coefficients in normal motion are appeared. On the other hand Stokes' solution are obtained by taking limits of low Reynolds number except the case of parallel motion with viscosity-ratio not equal to infinity.