Uniform Flow Mechanism of Non-Gaussian Features of Pressure on Square Cylinder

Abstract:

The extreme pressures and non-Gaussian feature of pressures are essential problems in the wind resistance design of the main structure and the surrounding structure, but the flow mechanism hasn’t been clarified yet. The non-Gaussian feature of wind pressure under the influence of the wind angle has been investigated using large eddy simulation (LES) at the Reynolds number of 22 000, and the relationship between the non-Gaussian region and the average field are analyzed. Flow mechanisms of extreme wind pressure are discussed based on instantaneous flow structure. The results show that the non-Gaussian region located at the rear corner and leeward side of the square cylinder, and there has not shown non-Gaussian feature at separation bubble region. The intermittent attachment vortex at rear corner creates extreme wind pressures on the surface of the square cylinder, which is closely related to the Karman vortex in the wake of the square cylinder. The extreme wind pressures on the leeward side of the square cylinder are caused by the cyclotron action of the Karman vortex in the wake of the square cylinder, and the positions of extreme wind pressures will change with the movement of Karman vortex.