Wind pressure on flat roof building in heterogeneous terrain
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摘要: 通过风洞测压试验，研究单个平屋面建筑物在两类均匀地貌，以及非均匀地貌边界层内的屋面风压分布变化规律。研究结果表明：均匀粗糙地貌下的屋面平均风压系数和脉动风压系数大于均匀平坦地貌，且脉动风压系数差别更显著；从粗糙地貌变化为平坦地貌的非均匀地貌中，用建筑物位置处动压无量纲化时，随着距地貌变化点的距离增大，平均风压系数变化较小，脉动风压系数逐渐减小且变化显著；用上游粗糙地貌动压无量纲化时，随着距地貌变化点的距离增大，屋面迎风分离区平均风压变化较小，迎风下游风压幅值增大，脉动风压幅值略有减小，但在过渡边界层范围内均变化较小；屋面整体平均风荷载的主要影响因素是来流动压变化。Abstract: With pressure measurement experiments in wind tunnel, wind pressure distribution on the flat roof of a building in two kinds of uniform terrains and one kind of heterogeneous terrain was investigated. The results demonstrate: the mean and fluctuating wind pressure coefficients on the roof in a uniform rough terrain are larger than those in a uniform smooth terrain, and this difference of the fluctuating pressure is more significant; When the pressure coefficients are normalized by the dynamic wind pressure of the building location, fluctuating wind pressure coefficients decrease significantly and mean pressure coefficients change slowly with an increase of the distance from the terrain change point to the building location in a rough to smooth heterogeneous terrain; When the pressure coefficients are normalized by the dynamic wind pressure of upstream terrain, mean pressure coefficients at the separation area change slowly, the amplitudes at the downstream roof area increase, and fluctuating wind pressure coefficients decrease slightly with an increase of the distance from the terrain change point to the building location, but these changes are small in the range of transition boundary layer; The main factor affecting total mean wind loads on the roof is the incoming dynamic pressure.
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Key words:
- heterogeneous terrain /
- boundary layer simulation /
- flat roof /
- wind tunnel test /
- wind pressure
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图 5 非均匀地貌平均风速和湍流度
Figure 5. Mean velocity and turbulence intensity in heterogeneous terrain
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