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为解决山区峡谷风场数值模拟过程中入口边界难以合理给定的问题,在中尺度气象模式(WRF)基础上利用多尺度耦合方法对山区峡谷桥址风场进行了精细化数值模拟。模拟过程中,首先基于WRF利用多尺度耦合的方法得到山区峡谷入口处的中尺度速度场信息,然后以入口边界位置风场波动情况为原则,对模拟的中尺度风场信息在耦合面进行分块,分块后分别运用多项式方法将其风速进行拟合,并通过UDF程序将拟合的速度赋给大涡模拟的入口边界。最后以张家界澧水大桥所在峡谷为研究背景,在桥址位置安装风速实时监测系统,将现场实测结果与所提方法的数值模拟结果进行了对比。研究结果表明:WRF的运行结果通过降尺后能较好地运用在山区峡谷风场CFD数值模拟的入口边界上,这种处理较好地解决了山区峡谷风场数值模拟过程中入口平均风的给定问题;分块多项式拟合插值方法解决了以往数值模拟过程中出现的“人为峭壁”问题;利用该方法可以较为准确地得到桥址处平均风速、风向角和风攻角等参数的分布情况。
In order to solve the problem that the inlet boundary can not be reasonably given in the numerical simulation of mountain gorge wind field, a multi-scale coupling method is used to refine the numerical simulation of the wind field at the mountain gorge bridge site based on the meteorological model of meso-scale (WRF). In the process of simulation, the mesoscale velocity field information at the entrance of mountain gorge is first obtained based on WRF using multi-scale coupling method. Based on the principle of wind field fluctuation at the entrance boundary, the mesoscale wind field information is simulated on the coupling surface After the block, the wind speed was fitted by polynomial method, and the speed of fitting was assigned to the entrance boundary of large eddy simulation by UDF program. Finally, taking the gorge where Zhangshui River bridge is located as the research background, a wind speed real-time monitoring system is installed on the site of the bridge site, and the field test results are compared with the numerical simulation results of the proposed method. The results show that the results of WRF can be well applied to the inlet boundary of CFD numerical simulation of wind field in mountainous gorge after the ruler is run down. This treatment can well solve the problem that the mean wind of inlet in the numerical simulation of wind field in mountainous gorge Given the problems, the block polynomial fitting interpolation method solves the problem of “artificial cliffs” in the past numerical simulation. By using this method, the parameters such as average wind speed, wind direction angle and wind attack angle can be obtained accurately Distribution.