| In actual engineering,the structure of two rectangular cylinders arranged inline is usually widely used.In the winding of the rectangular cylinder,there is usually separation of flow,reattachment of shear layers,and vortex shedding of wakes.Due to the interaction between the two rectangular cylinders arranged inline,their flow state and aerodynamic force characteristics are quite different from those of the single rectangular cylinder.In order to ensure the wind safety performance of such actual engineering structures,it is necessary to accurately grasp the aerodynamic force characteristics of two rectangular cylinders arranged inline.In view of the shortcomings of the research on the aerodynamic force characteristics of two rectangular cylinders arranged inline,this thesis took the two rectangular cylinders with a breadth to depth ratio of 1:4 as an example,and based on the method of wind tunnel test,the mean aerodynamic force coefficient,mean wind pressure coefficient,fluctuating aerodynamic force coefficient and fluctuating wind pressure coefficient of two rectangular cylinders in different wind direction angles(0°≤α≤90°)and different spacing ratios(the ratios of the center-to-center distance between the two rectangular cylinders to the breadth of the single rectangular cylinder L/B,1.2≤L/B≤8.0)were tested and analyzed,and the test results were compared with the test results of the single rectangular cylinder.The variation of aerodynamic force characteristics of two rectangular cylinders arranged inline with spacing ratio and wind direction angle were analyzed.The main conclusions of this thesis are as follows:(1)The variation of the mean aerodynamic force characteristics of two rectangular cylinders arranged inline with spacing ratio and wind direction angle was revealed.At 0°≤α≤30°,the mean drag coefficient of two rectangular cylinders at different spacing ratios is affected by the interference effect.At 30°<α≤90°,the mean drag coefficient aerodynamic interference effect of the upstream rectangular cylinder mainly occurs at 1.2≤L/B≤5.0,which is manifested as an amplification effect,and the maximum value is 1.54 times that of the single rectangular cylinder.At 0°≤α≤75°,the mean lift coefficient aerodynamic interference effect of the upstream rectangular cylinder mainly occurs at 1.2≤L/B≤3.0,which is close to the value of the single rectangular cylinder when the spacing is relatively large,and the mean lift coefficient of the downstream rectangular cylinder is positive number in the range of 1.2≤L/B≤3.0.The mean lift coefficient of downstream rectangular cylinder in the range of 0°<α<20° is larger overall than that of the single rectangular cylinder.(2)The variation law of fluctuating aerodynamic force characteristics of two rectangular cylinders arranged inline with spacing ratio and wind direction angle was clarified.According to the wind direction angle,the fluctuating aerodynamic force characteristics of two rectangular cylinders arranged inline with spacing ratio are classified.The fluctuating drag coefficient of the two rectangular cylinders shows a significant aerodynamic interference effect at 0°≤α<80°.At 0°≤α<20°,the fluctuating lift coefficient of the upstream rectangular cylinder shows an amplification effect in the range of 1.2≤L/B≤1.6,with a maximum value of 1.91 times that of the single rectangular cylinder and a decreasing effect in the range of 2.5≤L/B≤8.0.However,near the 0° wind direction angle,the fluctuating lift coefficient of the downstream rectangular cylinder shows a significant amplification effect in the range of 1.4≤L/B≤1.8,and the maximum value is 2.26 times that of the single rectangular cylinder. |
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