The flow past two cylinders having different diameters

The present investigation is concerned with the flow about two circular cylinders aligned parallel to each other and perpendicular to the flow, taking into account the case in which the diameter of the upstream cylinder is half that of the downstream cylinder. The experiments were performed in an open-circuit wind tunnel. The working section of the tunnel is 1.4 m long, and is octagonal in cross section with the opposite faces 0.46 m apart. The tunnel produces a uniform flow with a free-stream turbulence of less than 1 percent at 10 m/s. Measured data are presented with the aid of graphs for the case in which the cylinders are in tandem and for the case in which they are found in a staggered arrangement. Attention is given to the pressure distributions around a cylinder, the positions of the stagnation point, the Strouhal numbers, and the drag and lift coefficients.