长宽比对矩形截面高层建筑表面风压分布的影响研究

Research on influence of length-to-width ratios on wind pressure distribution of rectangular-sectioned high-rise buildings

为了研究长宽比对矩形截面高层建筑表面风压分布的影响,进行7个长宽比建筑的风洞试验,分析长边和短边正迎风时各立面的风压分布,从短边正迎风时侧风面的风压分布研究气流的分离和再附,计算得到面体型系数,并将面体型系数与荷载规范值进行比较。研究表明:短边正迎风时,迎风面的风压分布与长宽比无关,背风面风压比较均匀,长宽比越大负平均风压系数绝对值越小;当长宽比大于4∶1时,侧风面负风压绝对值由大变小再变大,气流发生分离、附着、再分离。试验获得的迎风面体型系数随着深宽比的增大而增大,背风面体型系数随深宽比的分布总体上与荷载规范一致。

In order to study the influence of length-to-width ratio on tile wind pressure distribution of rectangular-sectioned high-rise buildings, wind tunnel tests of seven huildings with various length-to-width ratios were done. The wind pressure distributions on various elevations when the short side and the long side of the building are in the windward direction were analyzed. The separation and re-attachment of the flow were investigated by using the wind pressure distribution on the crosswind surfaee when the short side of the building is in the windward direction. The total body shape coefficients were cah＇ulated and compared with the data obtained from the load code. Results show that the length-to-width ratio has insignificant influence on the wind pressure distribution on the wiudward surface when the short side of the building is in the windward direction. The wind pressures on the leeward surface are uniformly distributed and their absolute values will decrease if length-to-width ratio increases. When the length-to-width ratio is larger than 4： 1, the absolute values of negative wind pressure on the crosswind surface will change from large to small and to large again, indicating that separation, re-attachment and re-separation oecur in the flow. The body shape coefficients on the windward surface will increase if the depth-to-width ratio increases and their values of different depth-to-width ratios on the leeward surface have totally the same tendency with that regulated in the load code.