圆角处理对二维矩形柱体模型表面风压频域特性的影响研究

Effects of corner rounding modification on frequency domain characteristics of wind pressures on 2D rectangular prisms

利用刚性模型测压试验的方法,在低湍流度的均匀流场中测量了4种圆角处理(即圆角半径与模型迎风面厚度之比(圆角率)分别为0、5%、10%和15%)的截面宽厚比(截面顺风向宽度与迎风面厚度之比)分别为2、3和4的二维矩形柱体模型的表面风压,试验雷诺数为3.4×105。研究了圆角处理对3种截面宽厚比模型表面的3个典型测点的风压系数功率谱密度的影响,并分析了每种截面宽厚比模型的侧面风压分布及其风压相关性随圆角率的变化规律。研究表明:当圆角率为0和5%时,截面宽厚比为2的模型侧面不会出现气流再附现象,而当圆角率为10%和15%时,气流会再附于截面宽厚比为2的模型的侧面;圆角处理主要影响截面宽厚比为3和4的模型侧面的气流再附区的风压分布,而侧面气流分离区的负压绝对值基本不变;3种截面宽厚比的模型中,圆角处理对截面宽厚比为2的模型的侧面风压相关性影响最大。

Wind tunnel experiments were performed in low turbulence uniform flow to measure wind pressures on the surfaces of 2D rectangular prisms with various side ratios （2, 3 and 4, side ratio refers to the ratio of the along wind dimension to the across wind dimension） and various rounded comer ratios （0, 5% , 10% and 15% , rounded comer ratio refers to the ratio of the comer radius to the across wind dimension） , and the Reynolds number is 3.4 x l0s. The effects of rounded comers on power spectrums of pressure coefficients of three typical measuring points on the surface of models were analyzed. Moreover, the variation of mean pressure distributions and pressure correlations on the side surfaces of each model with the rounded comer ratio were studied. The results show that the 2：1 rectangular prisms with rounded comer ratios of 0 and 5% do not exhibit flow reattachment while the 2：1 rectangular prisms with rounded comer ratios of 10% and 15% experience complete flow reattachment. The influence of rounded corners on the pressure distributions of models with side ratios of 3 and 4 is mainly in the flow reattaehment region while the negative pressures in the separation bubble remain unchanged. The pressure correlation on the side surfaces of the 2：1 rectangular prism appears to be the most sensitive to the rounded comers for models with side ratios of 2, 3 and 4.