峡谷桥梁铁路周围测风站选址

Wind anemometer location determination on railway bridge in valley

基于Spalart-Allmaras方程的DES(分离涡模拟)湍流模型,采用流场计算软件FLUENT对峡谷桥梁线路周围流场进行数值模拟计算,得到峡谷桥梁线路周围的流场速度分布,研究结果表明:山体之间的间距越小对气流的加速作用越明显,10 m处最高速度增加量均在70%以上;山体倾角θ越小,速度增加越大。当θ由45°变化到25°时,桥梁位置z=10 m高度处的风速相对于入口初始速度的增加量由54.3%增加到79.8%;而峡谷隘口处z=10 m水平高处风速最大值Umax随着山体半径的增大逐渐增大,当山体半径达到300 m时,此处最大风速比入口标准风速增加了86.3%。同时风速在峡谷中间位置均存在一驻点,建议将测风站安装在隘口中心位置,可以适当避免安装误差引起的测量误差。

Using Detached-Eddy simulation （DES） based on Spalart - Allmaras formulation, this paper simulatedthe flow at the narrow valley in the mountain. The speed distribution around the bridge was obtained. The calculationresults show the acceleration effect is more obvious when the distance of two mountains is smaller, and that thespeed increased over 70% at the height of 10 meter. The smaller of the mountain slope angel 0, the greater thespeed increase. When mountain slope angel 0 changed from 45°to 25°, the wind speed at the bridge location that is10 meter high increased from 54.3% to 79.8% as compared to the wind speed of inlet. The wind speed at the middlebridge increases with increasing radius of mountain. When the radius of mountain reaches to 300 meter, it increasesabout 86.3% than the inlet speed. Meanwhile, there is a stagnation point of wind speed, where the windanemometer should locate to avoid the measurement error caused by installation error.