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Study on numerical simulation method for wind field over steep slope terrain

DOI：10.7511/jslx20200802001

 作者 单位 E-mail 郑德乾 河南工业大学 土木建筑学院, 郑州 450001 李亮 河南工业大学 土木建筑学院, 郑州 450001 方平治 中再巨灾风险管理股份有限公司, 重庆 400000 马文勇 石家庄铁道大学 土木工程学院, 石家庄 050043 ma@stdu.edu.cn

地形起伏是造成山地风场复杂多变的主要原因，其风场特性与基于均匀粗糙平面的风场有很大的区别。为准确模拟山坡地形风场，以坡角45°的简化陡峭山坡为研究对象，采用CFD数值模拟方法进行了流场分析，通过与风洞试验和各国规范对比，详细分析了网格分辨率、湍流模型和坡顶局部光滑处理等因素对数值模拟风场精度的影响。结果表明，采用基本网格尺度布置以及Realizable k-ε湍流模型，在坡顶位置的风压系数值与风洞试验存在一定偏差；在坡顶分离点处采用具有二阶连续性的曲线进行局部光滑，可使得数值模拟所得风速比和风压系数与试验结果更好地吻合，且光滑曲线的过渡段水平距离越短，模拟效果相对越好，坡顶位置的地形加速效应模拟结果与文献试验、中国以及澳大利亚规范具有更好的一致性。

Undulating terrains are the main reason for the complexity of a terrain wind field, and its characteristics are quite different from a flat and rough terrain.In order to accurately simulate the wind field around a steep hillside terrain, applicability of a numerical simulation method of flow field over a simplified steep uphill with slope angle of 45° is studied.The influence of grid resolution, turbulence model and local smoothing method on the accuracy of the simulated wind flow field is discussed in detail, by comparing with wind tunnel test and corresponding code data.Based on the basic grid scheme and realizable k-ε turbulence model, the simulation result agrees well with the wind tunnel data, despite discrepancy of wind pressure coefficients at the separation point of the slope top.By adopting second-order transition curve based local smooth measure at the slope top corner, good agreement can be ensured for both the simulated wind pressure coefficient and the wind velocity ratio with wind tunnel test results.Moreover, the simulation accuracy becomes better when the horizontal distance of the local smooth transition section gets shorter.The terrain speed-up effect obtained by present numerical simulation method is in good agreement with the wind tunnel test results reported in the literature, the corresponding Chinese and Australian codes.