An Effect of Gap Ratios at Four Circular Cylinders in a Staggered Configuration Near a Plane Wall

The flow that crosses the arrangement of four circular cylinders will form a certain flow pattern according to the geometry of the body contour, the distance between the cylinders, and the flow orientation (α), and generated aerodynamic forces, such as lift force, drag force, as well as induced vibration on the body. The force coefficients on four circular cylinders in an equispaced arrangement with a staggered configuration located near a plane wall were calculated through the pressure distributions measurement. The pressure distributions on each cylinder surface and the plane wall were measured for various gap ratio values of G/D= 0.0 and 0.2 (G, the gap between cylinder to the plane wall; D, diameter) and L/D= 2.7 (L, gap spacing between cylinders) in a uniform flow at a Reynolds Number of 1.743 x 104. The results show that the drag and lift coefficients on the cylinders depend on the gap ratio value of G/D. The drag coefficient decreases, when the amount of G/D increases, especially on the upstream cylinders. The lift coefficient on the upper-downstream cylinders has a significant value more than other cylinders at a small spacing ratio.