Force Coefficient Characteristics on a Four Circular Cylinders in an In-Line Square Configuration near a Plane Wall at "Small Gap"

This paper presents the calculation of the force coefficients of four circular cylinders in equispaced configurations through their pressure distribution measurements. The pressure distributions on every cylinder surface and the plane wall were measured for a gap-diameter ratio of G/D=0.2 and various spacing-diameter ratio of L/D=2.0, 2.7, 3.0 and 4.0, in a uniform flow at a Reynolds Number of 5.3 x 10(4). The results indicated that the spacing-diameter ratio (L/D) gave the important influence on the drag and lift coefficients of the cylinders. Where, the coefficient of drag is decreasing, when the amount of L/D is increasing, especially on the upstream cylinders. The lift coefficient on the upperdownstream cylinders has significant value more than others cylinder at a small spacing ratio.