偏转风作用下方形截面超高层建筑风效应研究

INVESTIGATION OF TWISTED WIND EFFECT ON A SQUARE-SECTIONAL SUPER-TALL BUILDING

  • 摘要: 超高层建筑具有轻质、高柔等特性,是典型的风敏感建筑。受地形和科里奥利力影响,风向会沿高度方向改变,称为偏转风现象。该文基于风洞试验和数值模拟,依据Ekman螺线生成了不同偏转角的偏转风场,对偏转风场及其对应的常规边界层风场下方形截面超高层建筑的风效应开展对比研究。结果显示:在偏转风场下,建筑表面风压呈不对称分布,在抗风设计中考虑偏转风时,基底力矩和层间荷载的取值与边界层风场存在一定差异;通过数值模拟揭示了使方形超高层建筑产生较为明显非对称荷载的偏转角大小为10°左右,并通过本征正交分解(proper orthogonal decomposition, POD)和流场分析说明了偏转风的作用机理。该研究有助于进一步理解偏转风对超高层建筑的作用机理。

     

    Abstract: Super-tall building is sensitive to wind loading because of its light weight and high slenderness. Under the influence of topography and Coriolis force, the wind direction may change along the height, which is known as the twisted wind effect. In the wind tunnel test and numerical simulation of this study, the twisted wind fields (TWFs) with different yaw angles were generated following the Ekman spiral model. Wind effects on a square-sectional super-tall building under twisted wind and those under the conventional wind fields (CWFs) were analyzed. The results showed that: under the twisted wind effect, the wind pressure distribution on the building facades became asymmetrical. In addition, the values of the base moment coefficients and the local wind force curve may need to be reconsidered in TWF-resistant designs. Numerical simulation showed that only the TWFs with a maximum yaw angle over 10° may induce notable effect on the pressure distribution on building facades. Furthermore, by means of proper orthogonal decomposition (POD) and of flow field analysis, the mechanism of TWFs was explained. This study aims to provide a useful reference for wind-resistant design of super-tall buildings under twisted wind effect.

     

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