大跨翘曲屋盖风压分布的风洞试验与数值模拟

摘要

为了解大跨翘曲屋盖结构的风压分布特征,对某大跨翘曲屋盖进行了风洞试验和计算流体动力学数值模拟.首先,根据风洞试验结果分析了屋盖风压分布情况及门窗开启状态对风压分布的影响;然后,基于CFX软件平台,采用RNG κ-ε湍流模型模拟了该屋盖结构的平均风压分布,并将模拟结果与风洞试验数据进行了比较.研究结果表明:门窗开启对外风压影响较小,对内压有一定影响,开一边门窗时,屋盖会受到向上的升力,两边同时开启时,内压对屋盖有向下的吸力作用;采用RNG κ-ε湍流模型模拟大跨翘曲屋盖结构的平均风压分布具有较好的计算精度,可较准确地反映实际风压;屋面风压分布以吸力为主,风荷载最不利位置在翘曲边缘和屋面顶部区域;来流方向为翘曲向时,风流在翘曲边缘有较大的分离,在翘曲面有较强的漩涡产生,风流绕过建筑后,在来流方向建筑两侧会伴随着分离和漩涡产生,且在背风面会形成两个大的对称尾涡,而来流方向为凹曲向时,侧面和背风面的分离和漩涡并不明显.%In order to determine the wind pressure distribution characteristics of a large-span warpage roof structure,a wind tunnel test and numerical simulation were carried out for a large-span warpage roof.First,the distribution of roof pressure and influence of open doors and windows on the wind pressure distribution were analysed according to the wind tunnel test results.Then,the mean wind pressure distribution for the roof structure was simulated on a CFX software platform by using an RNG κ-ε turbulence model,and the simulation results were compared to the wind tunnel test data.The results showed that the open doors and windows yielded little influence on the external wind pressure,and non-negligible influence on the internal pressure.Specifically,when the doors and windows of one side were opened,the roof was subjected to an upward lifting force.Alternatively,when both sides were opened at the same time,the internal pressure resulted in a downward suction on the roof.The RNG κ-turbulence model was used to simulate the average wind pressure distribution of a large-span warpage roof structure,and was found to accurately reflect the actual wind pressure.The primary effect of wind pressure on the roof was suction,and the most unfavourable position of wind load occurred at the warping edge and in the rooftop area.When the flow direction occurred parallel to the warp direction,the wind flow yielded increased separation on the warp edge and a stronger vortex on the warp surface.Wind flowing around the building resulted in the separation and vortex occurring along both sides in the flow direction;additionally,two large symmetric trailing vortexes were formed on the leeward sides.However,there was no significant evidence of separation and vortex occurring on both sides when the wind flow was directed against warpage.