Foroutan H, Tang W, Heist D K, Perry S G, Brouwer L H, Monbureau E M
Computational Exposure Division, National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA.
Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA.
Atmos Environ (1994). 2018 Aug;187:117-130. doi: 10.1016/j.atmosenv.2018.05.053.
High fidelity, scale-resolving numerical simulations of flow and pollutant dispersion around several elongated isolated buildings are presented in this paper. The embedded large eddy simulation (ELES) is used to model flow and concentration fields for six test cases with various source-building geometries. Specifically, the influence of building aspect ratio, wind direction, and source location is examined with these cases. Results obtained from the present ELES model are evaluated using available wind tunnel measurements, including those of streamwise and spanwise velocities, turbulent kinetic energy, and streamwise, lateral, and spanwise pollutant concentrations. Comparisons indicate that the ELES provides realistic representations of the flow and concentration fields observed in wind tunnel experiments, and captures several complex phenomena including the lateral shift and enhanced descent of the plume for rotated/elongated buildings. Furthermore, the ELES provides a means to study the advective and turbulent concentration fluxes, plume shapes, and geometry of vortical structures that is used to examine turbulent transport of pollutants around buildings. We investigate the enhancement of vertical and lateral plume spread as the building aspect ratio is increased. In addition, through the study of advective and turbulent concentration fluxes, we shed light on the physics behind higher ground-level concentrations observed for rotated buildings.
本文给出了围绕几座细长孤立建筑物的流动和污染物扩散的高保真、尺度解析数值模拟。采用嵌入式大涡模拟（ELES）对六个具有不同源-建筑几何形状的测试案例的流动和浓度场进行建模。具体而言，通过这些案例研究了建筑长宽比、风向和源位置的影响。使用现有的风洞测量数据，包括流向和展向速度、湍动能以及流向、横向和展向污染物浓度的测量数据，对当前ELES模型获得的结果进行评估。比较结果表明，ELES能够真实地反映风洞实验中观察到的流动和浓度场，并捕捉到一些复杂现象，包括旋转/细长建筑物羽流的横向偏移和增强下降。此外，ELES提供了一种研究平流和湍流浓度通量、羽流形状以及涡旋结构几何形状的方法，用于研究建筑物周围污染物的湍流输运。我们研究了随着建筑长宽比增加，垂直和横向羽流扩散的增强情况。此外，通过对平流和湍流浓度通量的研究，我们揭示了旋转建筑物地面浓度较高背后的物理机制。
