基于LBM的典型建筑布局树木风环境模拟

Numerical Simulation of Wind Environment for Trees with Typical Building Layouts Based on LBM Method

在建筑方案设计阶段定量评估景观绿植对建筑风环境影响,对于提高行人区域热舒适性具有重要实践意义。结合格子玻尔兹曼计算流体力学方法和多孔介质模型,开展了边界层流场-建筑-树木耦合模拟和关键参数验证,针对城市街道区域典型矩形建筑平面布局存在的风速加速现象,开展树木挡风效应分析。研究结果表明:模拟方法能够重现出与试验吻合一致的树木尾流区平均风速和湍流特征;基于不同阻力系数的树木透孔率对树木背风区下游1H~3H范围内挡风效应影响明显;基于等效原则提出的圆柱体简化模型能够计算出与树木原型一致的挡风效应变化规律;建筑两侧和迎风端布置合理间距的树木能够减小矩形建筑两侧风速加速比和加速区域面积,可以通过经济合理的树木布置方案实现建筑周围风环境舒适度优化和通风廊道畅通。研究成果可应用于景观植被风环境优化设计,为方案设计阶段绿色建筑自然通风评估提供新的计算参考。

It is of practical significance for improving the thermal comfort of pedestrian areas,to quantitatively evaluate the effect of landscape green plants on wind environment of buildings in the architectural design stage.Combining with the lattice Boltzmann computational fluid dynamics method and the porous media model,the coupled simulation of boundary layer flow field⁃building⁃tree are carried out and key parameters are verified,and the tree blocking phenomenon is carried out for the wind speed acceleration phenomenon in the typical rectangular building layouts in the urban street area.The analysis results show that:the simulation method can reproduce the average wind speed and turbulence characteristics in the tree wake area that are consistent with the test;the penetration rate of trees based on different resistance coefficients has obvious influence on the wind shielding effect in the range of 1H~3H downstream of the leeward area of trees;the simplified cylinder model based on the principle of equivalence can conservatively calculate the wind resistance variation law of trees consistent with that of real trees;the trees with reasonable spacing on both sides of the building and the windward end can reduce the wind speed acceleration ratio on both sides of the rectangular building and the area of the acceleration area.The economic and reasonable tree layout scheme can optimize the comfort of the wind environment around the building and make the ventilation corridor unobstructed.The research results can be applied to the wind environment assessment of landscape vegetation,and provide a new calculation reference for natural ventilation design of green buildings in the scheme design stage.