复杂型体悬挑屋盖风荷载风洞试验与数值模拟

基于Fluent 6.1软件平台,将Realizablek-ε模型与非平衡壁面函数搭配使用,对位于海岛强台风地区的某海洋文化中心屋盖风压分布进行了计算流体动力学(CFD)数值模拟,同时也对该建筑进行了风洞试验。模拟结果与风洞试验数据的对比显示数值模拟可较准确地反映实际风压。风洞试验和数值模拟均显示悬挑屋盖受到了很大的吸力,对屋盖结构极为不利,对此问题采取在屋盖悬挑部分开洞的减压措施,以改善屋盖悬挑部分的受风特性。对开洞后的建筑进行了CFD建模与计算,结果表明在屋面前缘开洞可有效降低屋盖悬挑部分的最大风压和所受的竖向升力,大大改善屋盖结构的受力状态。

Wind tunnel test and numerical simulation of wind loads on complex cantilevered roofs

This paper describes the computational and experimental study on wind pressure of a cantilevered roof structure.Based on Fluent 6.1 soft platform with the Realizable k-ε Model and the Non-equilibrium Wall Functions,wind loads acting on the plate cantilevered roof of an ocean exhibition building which lies in an island were computed by computational fluid dynamics(CFD) method.Wind tunnel test of this building model with 1∶150 geometric scale was also carried out in a boundary layer flow with exponent of 0.12.Pressures on upper and lower surface of the roof were measured simultaneously to determine the net pressures on the cantilevered roof.Comparisons between the results from the present computation and the wind tunnel test were then performed,indicating that the precision of CFD numerical simulation technique is accurate enough to predict the mean wind pressure distribution on complex cantilevered roof for practical purpose.In order to mitigate wind load on cantilevered roof,geometric modification of roof is made and further CFD numerical simulations were performed to compute the wind loads on modified roofs.The numerical results show that the wind pressure coefficient on the windward roof areas can be reduced evidently by carving some holes in the costal margin of the roof.The vertical lift force on the whole roof structure is significantly decreased in the roof opening case.Therefore,the stress state on the cantilever is improved and the roof structure is more reasonable and economical.