Abstract
This paper deals with an experimental study on the fluid flow around two rotating circular cylinders. The surface roughnesses of the cylinders were smooth and rough respectively. The experiments were carried out in a wind-tunnel with a working section 300mm×50mm×500mm, the ratio lid of the spacing t between the center of two cylinders to outer diameter d of the cylinder was 1.75 constant. The surface-pressure distributions on the cylinders were measured in the range of Re=3.02×10^4〜8.11×10^4 and the drag and lift coefficients were determined from these measurements. The velocities in the wake were measured with a hot-wire anemometer. The flow patterns around the cylinders were visualized by a smoke tunnel. As a result, when the cylinders with rough surface were compared to the cylinders with smooth surface, it was found that the drag and lift of cylinders were decreased in smooth case.
