Numerical simulation of wind environment in the urban areas

In this paper,we would like to introduce a numerical simulated model of a typical area of City Changsha established based on the real data statistics made by the corresponding departments.As we know from our daily experience,the wind environment has been becoming more and more complicated as a result of setting up more and more high-rises.To some extent,it has made our urban living environment more and more unpredictable with the consequence unknown.The situation has pushed us to accomplish our 3-dimensional numerical study of the wind environment by means of computational fluid dynamics software. The results of our simulation help us to disclose the fact that unreasonable layout of the architectural complex has a harmful effect in many ways.As it can be seen,the wind flow of some areas in the architectural complex is sluggish due to circuitous and narrow streets,and diffusion of contaminants becomes more and more serious.With the ever increasing concentration of the high-rises,the velocity of the wind becomes higher due to the serious reduction of the wind-flowing space.In some areas of narrow streets,when the wind flows into the streets, the high blowing velocity of the wind has resulted in the street-canyon wind,which makes the pedestrians on the streets feel unpleasant and discomfort particularly in the cold winter days.There would also suddenly appear strong surface stress of the wind on the areas with clusters of high-rises the urban areas concentrated with high-rise building clusters.In addition,if the architects fail to pay enough attention to the variation of weather change and the wind-flowing directions,negative pressure effect would become more serious than what the architects would have expected(e.g.the effect on the glass curtain wall,and billboard),which tends to bring damage and even high-rise would fall off and cause disastrous consequences and even threaten the safety of the local pedestrians.In addition,more outdoor blowing wind(which is hotter in summer and colder in winter) infiltrating into the room through the building envelopes would increase the energy consumption due to the differential pressure changes to the front and the back of the high-rise buildings in the street canyon.Therefore,it is strongly recommended to take more thoughts when planning of new urban areas,which can be shown in our simulation to the wind environment of the architectural complicated situations.