世博轴膜面平均风压的数值模拟研究

基于Fluent 6软件平台,利用Realizablek-ε湍流模型对世博轴大跨膜结构屋面的平均风荷载进行了数值模拟研究。首先,通过与刚性模型测压风洞试验结果的对比,验证了数值模拟计算的有效性。然后,着重研究了周边建筑对膜表面平均风压分布的影响。最后,从数值模拟得到的流场信息分析了周边建筑对膜表面平均风压分布影响的机理。结果表明:周边建筑对膜表面局部风压分布有一定的影响,主要是由于上游建筑的"遮挡"改变了膜表面附近气流的流动状态,使建筑后面区域膜表面局部风压的绝对值有所减小,但随着上游建筑与膜结构之间距离的增大,这种影响逐渐减弱,并且远离上游建筑位置的膜表面风压基本不受影响。

Numerical simulation of mean wind pressure on membrane roof of EXPO-axis

Based on Fluent 6.0,numerical simulation of mean wind load on the long-span membrane roof of the EXPO-axis was made by adopting Realizable k-ε turbulent model.The validity of the simulated result was first verified by comparison of some typical simulated results with those from the wind tunnel test of the rigid membrane model.Then effects of surrounding buildings on the mean wind pressure distribution on the membrane were investigated.The mechanism of the surroundings' effect was finally discussed through analysis of the simulated flow field around the membrane.The results indicate that the surroundings have obvious effect on the mean wind pressure distribution on the membrane.The Absolute value of the local wind pressures on the part of the membrane behind the upstream buildings generally becomes small,which is mainly due to so called sheltering effect.However,the sheltering effect becomes weak with the increase of the distance between the membrane and upstream buildings.