Wind effect on square and rectangular staggered cylinders

Abstract

An experimental investigation of the mean pressure distributions around an isolated and a group of square and rectangular cylinders placed in a uniform cross flow is presented here. The cylinders had side ratios of H IDd1.0 (square) and 1.25 (rectangular), where D is section width normal to flow direction and H is the section depth along the flow direction. A constant free stream velocity of 13.5m/s was used for this purpose. Mean pressure distributions around each of the cylinders were measured for angle of attack varying from 0° to 45° in step of 5° in open circuit wind tunnel. In case group of cylinders, one square and two rectangular cylinders of identical dimension were mounted horizontally in the staggered form. The square cylinder was placed centrally in the upstream side and the other two rectangular cylinders were placed symmetrically in the downstream side with respect to tunnel axis. Pressure distributions around the cylinders were measured for the different longitudinal and transverse spacing of the cylinders. Measurements Were also taken for one rectangular and two square cylinders in staggered form. Finally, drag coefficients, lift coefficients, moment coefficients and total force coefficients were calculated by numerical integration, The drag on an isolated cylinder was higher in general than that on the same cylinder while it becomes part of a group. It may concluded that the group-2 (one rectangular and two square cylinders) attained more suitable condition (minimum drag) for the transverse spacing, L, ~ 2D than the others.