Research On The Wind Corridor Identification Method Of Valley City Based On Frontal Area Index Calculation

Under the influence of global warming and human activities,the urban heat island effect has become increasingly serious and haze weather frequently occurs,which has brought a series of problems of urban microclimate environment deterioration,and the health of urban residents has also been seriously threatened.Reasonable urban spatial layout can form a good ventilation space,improve the overall ventilation efficiency of the city,so as to alleviate the urban heat island problem and evacuate the stranded air pollutants in the city center.Therefore,the construction of effective urban wind corridor space is of great significance to the improvement of urban microclimate environment.Compared with plain cities,valley-type cities are usually accompanied by complex geographical elements such as mountains,valleys,ditches and rivers,which have physical functions such as blocking,lifting and guiding natural winds.These special geographical conditions often make the urban climate problems faced by valley cities more severe,and the construction process of their urban wind corridors more complex.However,due to the traditional research on the urban wind corridor system mostly focused on coastal or plain cities,the research on the wind corridor in valley cities is still in the blank.Therefore,the research on the identification of the wind corridor in valley cities will be a new subject with great significance and value.After summarizing the previous research results,it is found that the research methods and ideas of wind corridors in plain cities are not suitable for valley cities.Therefore,this paper takes Chongqing as the research object,firstly calculates the urban windward index,analyzes the urban windward index map under the dominant wind direction in summer and winter respectively,and conducts a quantitative study on the correlation between the urban windward index and various urban morphology parameters.Then,based on the windward index,the path space of the minimum resistance cost,which represents the potential ventilation corridor space,is calculated.On the basis of these path Spaces,wind corridors are identified according to the criteria of path frequency and Angle between path and dominant wind direction.Finally,CFD numerical simulation results and windward surface index were used to verify and analyze the identified wind corridors.In view of the existing shortcomings of these wind corridors,optimization and improvement strategies for wind corridors in valley-type cities were proposed.The paper identifies 11 summer corridors and 14 winter corridors in Chongqing,among which the west side corridors are better than the east in summer,while the north and south side corridors and the central space have better ventilation effect in winter.However,the ventilation index of summer corridors is generally higher than that of winter corridors.This study,the windward side index calculation method combined with numerical simulation method,the city launched a valley wind corridor recognition methods of exploratory research,and other types of urban wind corridor for the future research provides a certain reference value,and optimizing the valley city wind corridor space,improve its internal urban wind environment has a certain practical significance.