Surface pressure distribution on patterned cylinders under simulated atmospheric boundary layer winds

Summary Extensive research has been previously conducted on pressure distribution of cylindrical models under uniform and laminar flow conditions. However, typical civil structures such as high-rise buildings or towers are under the atmospheric boundary layer (ABL) conditions. Knowing this, the present research aims to quantify the effectiveness of surface patterns in reducing the suction zone under a simulated ABL condition. Two different surface patterns, U-grooved and V-grooved, were selected to be tested in wind tunnel. In addition to patterned cylinders, tests were also conducted on a smooth-surfaced cylinder, serving as the control of the experiment. An array of roughness elements was placed at the upstream end of the test section with the purpose of inducing ABL winds within the test section. Without the ABL wind, the cylinder covered in V-grooved riblets was most effective in reducing the suction zone followed by the U-grooved cylinder. With the simulated ABL condition, V-grooved cylinder continued to show decreased suction although the amount of decrease was less. Both grooved cylinders showed decreased peak pressure coefficients under the ABL condition compared to the non-ABL condition.