中文摘要：

为研究山区峡谷桥址区地形模型边界过渡段的合理形式，基于理想流体圆柱绕流推导出一类过渡段曲线，以理想二维平台地形为分析模型，采用CFD软件FLUENT对比研究了等效斜率为0．58的曲线过渡段与30°斜坡过渡段的气流分离特性及过渡后平均风场的分布特性，并比较了不同曲线过渡段的气流过渡总长度。研究表明气流从等效斜率为0．58的曲线过渡段过渡时，其过渡后的风速场分布特性与无过渡段时参考风速场分布特性的一致性要高于气流从30°斜坡过渡段过渡的，且其气流过渡总长度相对最短。研究结论可为山区峡谷桥址区风特性的复杂地形模型风洞试验和数值模拟研究提供参考。

英文摘要：

To study the appropriate boundary transition section shape of terrain model for mountains- gorge bridge site, a kind of transition section curves was derived based on the theory of flow around cylinder with ideal fluid. According to the different shapes of the curve transition section with equivalent slope of0.58 and the ramp transition section with included angle of 30°, an ideal two-dimensional platform terrain was used as the analysis model to comparatively analyze the flow separation behavior and the distribution characteristics of average wind field after airflow flowed along the two transition sections by CFD commercial software FLUENT. Furthermore, the total flow transition lengths of different curve transition section shapes were also compared. The results show that when airflow flows along the curve transition section with equivalent slope of 0.58, the distribution characteristics of wind velocity field after airflow flowed along it are much closer to the distribution characteristics of reference wind velocity field than those when airflow flows along the ramp transition section with included angle of 30°, and its total flow transition length is also the relative shortest. The research conclusions could provide some references for the complex terrain model stud- ies on wind characteristics over the mountains-gorge bridge site by wind tunnel test and CFD methods.