EFFECTS OF INTERFERENCE AMONG 3 EQUIDISTANTLY ARRANGED CYLINDERS IN AUNIFORM-FLOW

The effects of flow interference among three identical circular cylind ers, which were arranged in an equidistant triangular cluster with the ir axes perpendicular to the uniform flow, were studied al various inc idence angles to the uniform flow and at different splicing ratios. Th e static pressures around the circumference of each cylinder were meas ured individually and the drag and lift coefficients of each cylinder were determined at Reynolds number of 6.2 x 10(4) based on the diamete r of a single cylinder. The effects of flow interference among the thr ee cylinders are severe when the spacing ratios are small. When two cy linders arranged side by side are upstream of or behind the third one, the flow patterns are not symmetrical with respect to the uniform Row direction and the drag or lift coefficients of the two cylinders in t he side-by-side arrangement are not always equal to each other at smal l spacing ratios. The inclination angles to the uniform flow strongly influence the drag and lift coefficients, the direction of force exert ed on each cylinder and the flow patterns around the cylinders. The ef fects of interference among three cylinders become weak as the spacing ratios are increased. (C) 1998 The Japan Society of Fluid Mechanics I ncorporated and Elsevier Science B.V. All rights reserved.