Effects of Turbulence on the Pressure Distribution Around a Square Cylinder and Possibility of Reduction

Abstract

Abstract When a prismatic structure is subjected to air flow, especially at small angle of wind incidence, the separated shear layers may reattach onto the streamwise surface. The turbulent mixing in the shear layers and the extrainment of fluid results in highly fluctuating and strongly negative pressures under the reattaching shear layers. Wind tunnel tests were carried out to determine the pressure distribution around a square cylinder. It was found that an increase in turbulence, in particular fine scale turbulence, significantly altered the pressure distribution, the transverse force characteristic, and hence the galloping behavior of the square cylinder. When small vanes were fitted to the corners of the cylinder, and by maintaining a vent between the vane and the corner, the magnitude of the negative mean and peak pressure coefficients under the shear layer were substantially reduced.