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针对下击暴流整体移动对其水平风速的增大效应,采用数值模拟方法(CFD)得到全尺寸下击暴流不同径向位置的风剖面,并与线性叠加算法得到的水平移动下击暴流的风剖面进行对比,发现线性叠加方法在R/D≤1.1径向区间内不能准确体现下击暴流整体水平移动对沿其整体移动方向上的纵向风速剖面的影响。为此,本文提出了非线性预测方法,准确地得到了下击暴流不同水平移动速度条件下的不同径向位置风剖面;结合风剖面计算该公式与大气边界层风速分布,研究了地表粗糙度、10m高度参考风速、下击暴流初始出流速度等对下击暴流影响高度的作用。结果表明:整体水平移动下击暴流影响高度的最大值出现在R/D≤1.13范围;地面粗糙度增加明显降低了该影响高度;整体移动速度增大显著增加了下击暴流的影响高度。
Aiming at the increasing effect of the overall movement of the downburst on its horizontal wind speed, a numerical simulation method (CFD) was used to obtain the wind profile of the full-scale downburst in different radial positions and compared with the horizontal movement under the linear superposition algorithm It is found that the linear superposition method can not exactly reflect the influence of the overall horizontal movement of the downburst on the longitudinal wind velocity profile along its entire moving direction in the R / D≤1.1 radial interval. For this reason, a nonlinear prediction method is proposed in this paper, and the wind profile at different radial positions under the different horizontal velocity of the downburst is obtained accurately. Combining the wind profile and the atmospheric boundary layer wind velocity distribution, Degree, the reference wind speed of 10m, the initial outflow velocity of the downburst, etc., have a great effect on the downburst. The results show that the maximum value of the height of the strikeburst under the whole horizontal movement appears in the range of R / D≤1.13. The increase of the ground roughness obviously reduces the influence height. The increase of the overall moving speed significantly increases the influence height of the downburst, .