改进大涡模拟方法及其在建筑结构风场模拟中的应用  

Improved large eddy simulation and its application for simulation of wind field around buildings

作　　者：周岱[1] 涂佳黄[1] 黄橙[1] 

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海200240

出　　处：《建筑结构学报》2010年第S2期170-175,共6页Journal of Building Structures

基　　金：高等学校博士学科点专项科研基金项目(200802480056);国家自然科学基金项目(50778111)

摘　　要：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。The wind field around structure and wind pressure distribution upon the structure are key issues in the wind-resistant design of building structures.In this paper,a stabilized finite element technique is developed to predict the characteristics of wind flow with high Reynolds number,which combines by streamline upwind Petrov-Galerkin(SUPG) stabilized method and the three-step finite element method for large eddy simulation(LES).Weak form LES motion equation is combined with the SUPG stabilized term for the spatial finite element discretization,and explicit three-step scheme is implemented for the temporal discretization where the pressure is computed from Poisson equation which is derived from the incompressible condition.A simple and fast spatial test filter based on a dynamic subgrid-scale(DSGS) model of unstructured finite element grids is developed for low data storage and computational cost.Progress of node-based filter and generalized box filter are used for the calculation of values of filtering procedure.The present method can simulate the wind field around building structures steadily and accurately and is an effective approach for studying the characteristics of wind field and wind loads.The numerical example of three-dimensional wind field around a building with Re = 4.2×105 is performed using DSGS model based on the present method.Mean and instant wind fields including such aspects as streamlines,velocities,pressures and vorticities are analyzed,and the three-dimensional large-scale vortex structures of the wind flow around a building are investigated and visualized.

关 键 词：大涡模拟 动态亚格子模型 稳定化有限元 高雷诺数 风场 

分 类 号：TU312.1[建筑科学—结构工程]