Experimental Study On Reynolds Number Effect Of Mean Wind Load Characteristics Of Rectangular Cylinders With Rounded Corner

Rectangular cylinders are widely used in practical engineerings,such as high-rise buildings,bridge towers,and bridge piers.Rounding corner treatments of rectangular cylinders can effectively reduce the wind load and improve the wind-induced vibration performance of the structure.Preview studies have shown that the wind load characteristics of rectangular cylinders with rounded corner have an obvious Reynolds number effect.Ignoring the Reynolds number effect of the structure may cause large errors in the wind load and wind-induced vibration analysis of the structure.The existing literature mainly studies the Reynolds number effect of wind load characteristics of rectangular cylinders with small rounded corner ratios under specific wind direction angles.It is of great significance for structural wind resistance design to fully grasp the Reynolds number effect of rectangular cylinders with different rounded corner ratios under different wind direction angles.The rectangular cylinders with a width-to-thickness ratio of 2 and rounded corner ratios of 0,0.1,0.2,0.3,0.4,and 0.5 were tested by rigid pressure-measured model wind tunnel tests.The Reynolds number effects of mean wind load characteristics of rectangular cylinders with rounded corner were studied under various Reynolds numbers(0.8×10~5～3.6×10~5)and various wind direction angles(0°～25°).The effects of different rounded corner ratios and different wind direction angles on the Reynolds number effects of the mean wind pressure coefficients and the mean aerodynamic force coefficients of the rectangular cylinders with rounded corner were analyzed.The main conclusions are as follows:(1)Under vertical wind direction angle(α=0°),the Reynolds number effect of the mean wind pressure coefficients of rectangular cylinders with rounded corner increase first and then decrease with the increase of the rounded corner ratio.The model with the rounded corner ratio of 0.2 has the strongest Reynolds number effect.The area with the strongest Reynolds number effect of the mean wind pressure coefficients of rectangular cylinders with different rounded corner ratios is the round corner of the windward surface.(2)The range of the mean wind pressure coefficients’Reynolds number effect of rectangular cylinders with different rounded corner ratios affected by the wind direction angle increase first and then decrease with the increase of the rounded corner ratio.The most affected by the wind direction angle is the rectangular cylinder with the rounded corner ratio of 0.3.The maximum absolute value of the mean wind pressure coefficient of rectangular cylinders with different rounded corner ratios is 5.64,and the corresponding rounded corner ratio is 0.4,which appears near the corner of the windward surface of the rectangular cylinder.(3)Under vertical wind direction angle,the mean drag coefficients of rectangular cylinders with rounded corner ratios of 0.1,0.2,and 0.3 have obvious Reynolds number effect,the mean drag coefficients decrease with the increase of Reynolds number.The mean drag coefficients of rectangular cylinders with rounded corner ratios of 0.4 and0.5 have no obvious Reynolds number effect.(4)The range of the mean aerodynamic coefficients’Reynolds number effect of rectangular cylinders with rounded corner affected by the wind direction angle increase first and then decrease with the increase of the rounded corner ratio.The most affected by the wind direction angle is the rectangular cylinder with the rounded corner ratio of0.3,which is all the wind direction angles in the test(0°～25°).The mean aerodynamic force coefficients of rectangular cylinders with rounded corner ratios of 0.3,0.4,and0.5 change significantly at high Reynolds numbers at some wind direction angles.