Simulation Study On Wind Environment And Pollutant Diffusion In City Comprehensive

With the development of urban construction and the prosperity of business, more and more urban complex across the country has been built up. For this new form of community building, the research on its outdoor air quality has a great significance. Wind environment and outdoor pollutants around urban complex as parts of the physical environment, it is closely related to people’s lives, and also have important implications on the outdoor environmental comfort of urban complex, people’s health and safety aspects. Therefor, researches on outdoor wind environment and pollutant dispersion in urban complex have theoretical significance and practical value.Urban complex district outdoor environment air flow and air quality is affected by many factors, including the design factors and the natural factors. This paper mainly studied the influence of different height of skirt building and tower building on the outdoor environment of air flow and pollutant distribution in the view of design factors. For the natural factors, this paper studied the effects of wind direction on the outdoor environment of air flow and pollutant distribution. And for the influences of natural factors, the temperature difference between the air and wall and the outside temperature gradient has been taken into consider.Then, take a simulation analysis on the outdoor wind environment and pollutant diffusion of unban complex under different factors based on the CFD simulation software-FLUENT. Find the general rule of the outdoor wind field and the pollutant diffusion distribution around the complex building. This paper mainly studies the outdoor wind environment and pollutant diffusion of typical urban complex under four different conditions including the building height, the wind factors, the temperature difference between the air and wall as well as the outdoor temperature gradient. The characteristics of eddy current distribution and the pollutants concentration distribution under different temperature gradient and the change of building height in typical complex building have been summarized by analyze each key section of the wind field and pollutant concentration distribution of complex outdoor wind environment.The results show that the changes of building height will impact on wind field in complex buildings and leading to the different pollutant diffusion law. When the tower height is changeless while skirt building height is increased gradually, the wind environment in complex buildings also produces changes, the eddies on each cross-sections will expand its current range. And the pollutant concentration on pedestrian street and its top place will be increased. When the height of the skirt building remains constant, tower building which’ layout is previous high after low will produce large range, number of eddies current than the one previous low after high layout, so it is easier to make pollutant accumulation. The change of wind direction as one of the natural factors will have a clear impact on pollutant diffusion. And the temperature difference between the air and wall will also have an impact on pollutant dispersion while the outdoor temperature gradient have not.The simulation results has a certain reference value for the building height design, complex layout, the selection of underlying surface materials and improve air quality in complex outdoor wind environment.