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通过对平板湍流边界层进行大涡模拟,采用拟周期边界条件维持湍流边界层厚度稳定,提取速度和压力时程作为低矮建筑绕流模拟之脉动入流边界条件,研究脉动入流下的低矮建筑绕流特性。研究结果表明:入流边界特性对网格变化适应性良好,其平均速度剖面、湍流强度、流速频谱特性基本符合空旷地貌风场特性;脉动入流下,建筑表面的平均风压系数、脉动风压系数的计算结果与风洞试验结果基本吻合。受雷诺数及湍流强度的影响,流动分离区负压与试验值存在一定差别;屋盖上分离区风压时程具有非高斯概率特性,尤以气流分离较剧烈的屋盖迎风边缘及屋盖两侧风压的非高斯特性明显,该特征与风洞试验基本一致;受非高斯特性的影响,建议峰值因子g取4.5~5.5。
The large eddy simulation of the turbulent boundary layer in the plate is carried out, and the thickness of the turbulent boundary layer is maintained by using the quasi-periodic boundary conditions. The extraction velocity and pressure time history are used as the inflow boundary conditions for simulating low-flow around the building. Flow characteristics. The results show that the inflow boundary characteristics have good adaptability to the grid changes, and the average velocity profile, turbulence intensity and flow velocity spectrum are basically consistent with the open landform wind field characteristics. Under fluctuating inflow, the average wind pressure coefficient, the fluctuating wind pressure coefficient The calculated results are in good agreement with the wind tunnel test results. Under the influence of Reynolds number and turbulence intensity, there is a certain difference between the negative pressure in the flow separation zone and the test value. The pressure history in the separation zone on the roof has the characteristics of non-Gaussian probability, especially in the more windward separation of the roof windward edge and the roof The non-Gaussian characteristic of the wind pressure on both sides is obvious, which is basically consistent with the wind tunnel test. It is suggested that the peak factor g be 4.5-5.5 due to the non-Gaussian characteristics.