Effect Of Building Height Density And Arrangement On Urban Wind Environment

An increasing number of high-rise buildings have been recently built in cities.The rapid increase of urban buildings has caused a series of negative effects.Wind environmental problems,including poor ventilation,the wall effect,and wind noise,have attracted public attention,especially during the outbreak of global crises such as COVID-19 that can cause many deaths.Although studies have focused on methods for increasing wind environment,quantitative research on the influence of the height and density and irregular building arrangements of buildings on the multi-aspect wind environment remains limited.The following works are carried out in this paper.Firstly,two groups of 2D numerical experiments(include high-density and high-rise buildings model)are set up to simulate the wind speed field corresponding to the two-dimensional stepped residential buildings with different height and density.The wind environment is evaluated according to the high-rise wind noise,wall effect,and street ventilation.Secondly,13 wind speed fields corresponding to six 3D building arrangements(linear,incline,convex,concave,M-shape,and V-shape configurations)with different street widths and building offsets were simulated by using COMSOL Multiphysics software.Thirdly,2D simulation and 3D simulation are compared.Conclusions are follows,(1)For high-density buildings model,the wind noise,wall effect,and street ventilation are lower,weaker,and better,respectively,with low building heights than with high building heights.We suggest the building height should not exceed 30 m in this condition.(2)For high-rise buildings model,the wider the street canyon,the lower is the highrise wind noise and the better is the street ventilation.The wall effect is weak when the Aspect Ratio(building height/street width)is between 0.67 and 2.We suggest the street width should exceed 24 m in this condition.(3)The standard k–? model provided a better prediction than the realizable k–? model.Furthermore,small street width and large building offset enhanced street canyon ventilation,and the concave configuration was the best among the six configurations.The M-shape and V-shape configurations were slightly inferior to the concave configuration in terms of wind speed uniformity of different street canyons.(4)Although the calculation time of two-dimensional simulation model is short,its application range is limited,which can only represent the infinite building.The three-dimensional simulation requires more computation but is closer to the real situation.