格栅湍流风场风参数变化规律的风洞试验研究

Wind tunnel experimental study of the variation of wind parameters in grid turbulent wind field

格栅湍流风场常用于研究来流风参数对结构风效应的影响规律与作用机理。本文对不同格栅湍流风场的风参数随横栅板起始高度、孔隙率、距离和栅板宽度的变化规律进行了研究,结果表明:横栅板起始高度为横栅板间距一半时,格栅湍流风场的均匀性较好。湍流积分尺度离散性较大,可采用一定范围内的湍流积分尺度的平均值衡量试验横断面湍流积分尺度的总体大小。随着距离增大,湍流强度呈指数衰减趋势,湍流积分尺度呈增大趋势;随着栅板宽度增大,湍流强度和湍流积分尺度均增大;基于试验结果提出了湍流强度和湍流积分尺度关于距离和栅板宽度的计算公式。根据风参数的变化规律,调试出了两组特定的格栅湍流风场,一组湍流强度接近,湍流积分尺度相差较大,反映了脉动风的涡旋结构不同;另一组湍流积分尺度接近,湍流强度相差较大,反映了脉动风的能量大小不同。上述研究结果为下一步研究风参数对高层建筑风效应的影响规律打下了基础。

Grid turbulent wind field is commonly applied to study the influence of wind parameters on structural wind effect and its mechanism. In this paper, the variation of wind parameters of different grid turbulent wind fields with the initial height, porosity, distance and grid width of the grid plate is studied. Results show that when the initial height of the grid is half of the horizontal grid spacing, the uniformity of the turbulent wind field in the grid is better. The scale of turbulence integral is discrete, and the mean value of turbulence integral scale in a certain range can be used to measure the total scale of cross section turbulence integral. With the increase of distance, the intensity of turbulence decreases exponentially and the scale of turbulence integral increases. The turbulence intensity and turbulence integral scale increase with the increase of grid width, and the formulas of turbulence intensity and turbulence integral scale about distance and grid width are obtained by fitting. According to the variation pattern of wind parameters, two groups of special grid turbulent wind fields are adjusted. One presents similar turbulence intensity and different turbulence integral scale reflecting different fluctuating wind vortex. And another presents similar turbulence integral scale and different turbulence intensity reflecting different fluctuating wind energy. Based on such works, studies on wind effects on high-rise buildings under various wind characteristics will be carried out.