The twisted wind effect has attracted increasing attention among scholars due to its significant influence on the wind loads and wind induced responses of high-rise buildings. Nowadays, it is still challenging to simulate twisted wind flows (TWFs) with larger wind twist angles (WTAs) in the wind tunnel test. Compared to wind tunnel test limitations, the large eddy simulation (LES) offers an effective tool to simulate a broader WTA range. Several state-of-the-art numerical studies have generated TWFs that rely on multiple velocity inflow boundary (MVIB), but it results in vast computational domains and substantial abnormal pressure fluctuations. This paper proposes a single velocity inflow boundary (SVIB) method for modeling TWFs, which can significantly reduce the computational domain size without losing accuracy. Based on the SVIB method, we simulate TWFs with four WTAs (i.e., 0°, 25°, 35°, 45°) and conduct a comprehensive analysis of the influence of WTA and wind direction angle on both the wind load characteristics of and the flow patterns around a high-rise building. The results show that the TWFs will twist the vortex topology and trajectory, and the maximum extreme local resultant force coefficient under 35TWF is larger than that under SWF by around 10 %. The positive and negative wind pressures can simultaneously occur on a special surface at large WTAs (e.g., 35°, 45°), which may impose significant shear forces on the intermediate layers. The wind veering effect enhances the contribution of vortex shedding to the longitudinal fluctuating wind loads and the influence of incoming turbulence on lateral fluctuating wind loads. This study contributes to providing a more effective LES method to simulate TWFs with large WTAs and to reveal the effect of large WTA on the wind load characteristics of high-rise buildings under TWFs and the underlying flow mechanism, which is beneficial to the future wind-resistant design of skyscrapers.

中文翻译：

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基于LES的扭曲风流下高层建筑风荷载及流态研究


扭曲风效应因其对高层建筑风荷载和风致响应的显着影响而日益受到学者们的关注。如今，在风洞试验中模拟具有较大风扭转角（WTA）的扭转风流（TWF）仍然具有挑战性。与风洞测试的限制相比，大涡模拟 (LES) 提供了一种有效的工具来模拟更广泛的 WTA 范围。一些最先进的数值研究已经生成了依赖于多速度流入边界 (MVIB) 的 TWF，但它会导致巨大的计算域和显着的异常压力波动。本文提出了一种用于 TWF 建模的单速度流入边界（SVIB）方法，该方法可以在不损失精度的情况下显着减小计算域大小。基于SVIB方法，对具有4个WTA（即0°、25°、35°、45°）的TWF进行模拟，综合分析WTA和风向角对风荷载特性和风荷载特性的影响。高层建筑周围的流动模式。结果表明，TWF会扭曲涡旋拓扑和轨迹，35TWF下的最大极限局部合力系数比SWF下大10%左右。正负风压可以同时出现在大WTA（例如35°、45°）的特殊表面上，这可能对中间层施加显着的剪切力。风向转向效应增强了涡脱落对纵向脉动风载荷的贡献以及来袭湍流对横向脉动风载荷的影响。 本研究有助于提供更有效的LES方法来模拟大WTA下的TWF，揭示大WTA对TWF下高层建筑风荷载特性的影响及底层流动机制，有利于未来风能的研究。摩天大楼的抵抗设计。