Large-eddy simulation of stratification effects on dispersion in urban environments
This paper focuses on investigating thermal buoyancy effects on dispersion of approach flows and local heat transfer from/to buildings by taking the DAPPLE site as the test case but for varying wind direction and magnitude. Firstly, based on the BT tower data, only weakly unstable conditions (i.e. Richardson number |Ri|<1) of approach flows were considered, with adiabatic boundary conditions at the ground and building surfaces. It was found that the predicted concentration in the far field was significantly reduced. Secondly, numerical experiments were performed, i.e. using various Richardson numbers. It was found that the modelled mean concentration for bulk Richardson number -0.9 was in reasonable agreement with field data at all stations. Thirdly, to understand the effects of weakly local unstable conditions, nonadiabatic boundary conditions at ground and building surfaces were implemented as well as weakly unstable conditions in the approach flows. No significant difference was found comparing with those using adiabatic boundary conditions. These simulations suggest that stratification effects on dispersion in weakly unstable conditions (e.g. in London) are not negligible.
stability scalar building CFD weather-scale
Zheng-tong Xie
School of Engineering Sciences,University of Southampton Southampton,UK
国际会议
9th International Conference on Hydrodynamics(第九届国际水动力学会议 ICHD2010)
上海
英文
995-1000
2010-10-11（万方平台首次上网日期，不代表论文的发表时间）