Experimental Study On Reynolds Number Effect Of Extreme Wind Pressure Of Square Cylinders With Rounded Corner

Due to the excellent aerodynamic performance,square cylinders with rounded corner are widely used in many engineering structures.When strong wind act on the buildings,pressure will be generated on their surfaces,which will harm the envelope structures such as glass curtain walls.Previews studies have shown that Reynolds number effect on the extreme wind pressure of the square cylinders with rounded corner is obvious.Therefore,it is necessary to accurately obtain the extreme wind pressure of the rounded corner squares column under different Reynolds numbers for the wind resistance design of the envelope structures.At present,due to the lack of in-depth research on the non-Gaussian characteristics of the fluctuating wind pressure on the rounded square cylinders,the research on the Reynolds number effect of its extreme wind pressure is also insufficient.In view of this,the fluctuating wind pressure time history of square cylinders with different rounded corners was obtained by rigid pressure-measured model wind tunnel tests in this study.On the basis of in-depth analysis of the non-Gaussian characteristics of fluctuating wind pressure,the variation law of extreme wind pressure coefficients of square cylinders with different rounded corner ratios with Reynolds number were analyzed.The main work of present paper includes following several aspects:(1)Firstly,the non-Gaussian characteristics of wind pressure time history for standard square cylinder and square cylinders with rounded corner were analyzed.The rounded corner ratios are 0.1,0.2,0.3 and 0.4.Then,the model surface was divided into Gaussian regions and non-Gaussian regions,and the variation of non-Gaussian regions distribution characteristics on the surface of standard square cylinder and rounded square cylinders with Reynolds number were researched.Finally,the peak factors of measurement points were calculated and analyzed.The results show that the non-Gaussian region of the standard square cylinder is mainly concentrated on the leeward side within the range of the test Reynolds numbers,and the change with Reynolds number is not obvious.After rounding,the distribution of non-Gaussian regions of rounded square cylinders varies significantly with Reynolds number,nonGaussian regions appear at the upwind corner within a certain range of Reynolds numbers.The peak factors of measurement points in non-Gaussian regions are significantly greater than the standard value.(2)The variation rules of the positive and negative extreme wind pressure coefficients of the square cylinders with different rounded corner ratios with Reynolds number were compared and analyzed.The results show that the Reynolds number effect of the extreme wind pressure coefficients on the crosswind side and leeward side of the standard square cylinder are obvious.The maximum absolute value of the negative extreme wind pressure coefficient occurs in the middle and rear of the crosswind side,and the absolute value is 4.34.The extreme wind pressure coefficients of rounded square cylinders changes from symmetric distribution form to asymmetric distribution form with the increase of Reynolds number.The Reynolds number effect on the extreme wind pressure coefficients of the square cylinder with rounded corners are most obvious on the crosswind surface.The area with the strongest Reynolds number effect gradually expands from the windward corner point to the crosswind surface with the increasing rounded corner ratios,and the extreme points gradually move backward.With the increase of the rounded corner ratios,the Reynolds number effect first strengthens and then weakens.When the absolute value of the negative extreme wind pressure coefficient reaches the maximum,the corresponding rounded corner ratio is 0.2,which appears near the windward corner with an absolute value of 5.8.