Effect of Spacing between Two Adjoining Circular Cylinders on Flow around Two-Dimensional Circular Cylinder Rows. 2nd Report, Two and Three Rows of Transverse Arrangement.

Abstract

This paper describes an effect of spacing between two adjoining circular cylinders on flow around two-dimensional circular cylinder bundles. The experiment was carried out in an N. P. L. blow-down type wind-tunnel with a working section of 500 mm×500 mm×2000 mm, and under the Reynolds number 1.3×104. The surface-pressure distributions on the circular cylinder were measured and the drag coefficient was determined from these measurements. The flow-pattern around circular cylinders was observed. The power spectrum in the turbulent wake behind circular cylinders was also measured. It was found that the pressure on the rear surface of circular cylinders becomes lower and the drag coefficient increases as the spacing ratio decreases, while the step-change in the drag coefficient occurs at the spacing ratio where the flow pattern around the downstream circular cylinder changes.