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掌握结构周围风场及其特性,是开展建筑结构抗风设计的基础。结合流线迎风Petrov-Galerkin(SUPG)稳定化方法和三步流体有限元方法,提出一种适用于模拟结构周围风场的高雷诺数风流动的大涡模拟方法(LES)。将亚格子运动方程弱解形式与SUPG稳定项相结合进行有限元空间离散,对时间离散采用高精度的显式三步有限元方法,压力场通过求解泊松方程得到。结合节点滤波函数和广义箱式滤波函数,发展了一种基于非结构化有限元网格的简洁、快速的空间滤波技术,该技术可使动态亚格子模型(DSGS)计算时储存量低且计算量小。所提方法可对建筑结构周围风场进行稳定、快速和精确的数值模拟,是分析结构周围风场特性和结构风荷载的有效工具。算例中,应用建设的动态亚格子模型(DSGS)模拟立方体建筑周围风场(雷诺数为420 000),并对平均风场和瞬时风场在流线、速度场、压力场和涡量场等方面进行了分析,详细阐明了建筑物表面(三维)大尺度涡结构并实现数值可视化。
Grasping the wind field and its characteristics around the structure is the foundation for wind-resistant design of the building structure. Combined with the streamlined windward Petrov-Galerkin (SUPG) stabilization method and the three-step fluid finite element method, a large eddy simulation method (LES) is proposed for high Reynolds-number wind flows that simulate the wind field around the structure. The finite element space discretization is carried out by combining the weak solution form of sub-grid sub-movement equations with the SUPG stable item, and the explicit three-step finite element method with high precision is adopted for the time discretization. The pressure field is obtained by solving the Poisson equation. A simple and fast spatial filtering technique based on unstructured finite element mesh is developed by combining node filtering function and generalized box filtering function. This technique can make the storage of dynamic sub-lattice model (DSGS) low and calculate Small amount. The proposed method can perform stable, fast and accurate numerical simulation of the wind field around the building structure and is an effective tool to analyze the wind field characteristics and wind load around the structure. In the example, the dynamic sub-lattice model (DSGS) of the construction is used to simulate the wind field (Reynolds number is 420 000) around the cube building. The average wind field and instantaneous wind field in the streamline, velocity field, pressure field and vorticity field And other aspects of the analysis, a detailed description of the building surface (three-dimensional) large-scale vortex structure and the realization of numerical visualization.