桥址峡谷地貌风场特性的CFD模拟

摘要

For long-span bridges on gorge terrain, the determination of wind characteristics prevailing at bridge deck level may be a challenge. In this paper, a large bound of topography at bridge site was first obtained in Google Map. Then altitude data on discrete points of interest was extracted by Autocad. Final-ly, Imageware was employed to form a terrain surface. With a computational domain built with the terrain surface included, the wind field at the bridge site was numerically simulated with Reynolds-Averaged Navi-er-Stokes equations and the standard turbulence model. Considering different incoming wind conditions, wind characteristics on the bridge site, such as wind profile, angle of attack, as well as yaw angle along the bridge axis were determined. Also, the wind flow along the gorge can be visualized, which provided a direct insight for wind environment. The present method provides an effective approach for wind parame-ters on a wide range of complex terrains.%对峡谷地貌上的大跨度桥梁而言,其桥址周围风场特性的确定可能非常困难.本文首先从Google Earth得到桥址附近大范围区域的地形图,然后借助Autocad获得区域内离散点的高程数据,再通过逆向工程软件Imageware拟合出桥址周围地形曲面.通过形成以该曲面为底面的计算域并实施网格划分,采用雷诺时均N-S方程和标准k-ε湍流模型,数值模拟了不同来流条件下计算城内的流动特征,获得了桥址附近不同位置处的风场数据,再现了峡谷地貌上的气流运动,为大跨度桥梁抗风研究提供了重要的风场参数.