Influence Of Green Space Layout On Wind Environment In Zhengzhou Residential District

The quality of wind environment in residential communities is closely related to the physical and mental health and comfort of residents.This research systematically analyzes the influence mechanism of urban green space form,the layout of buildings and units,and landscape spatial factors on wind environment,through actual measurement and numerical simulation of the wind environment in different spaces of urban residential areas in the north temperate continental monsoon climate zone,and this provides a feasible guidance and control design strategy for optimizing the urban wind environment.The experimental record of the wind environment in residential areas includes two aspects:?During the period from 8:00 to 19:00 on September 12-15/2015,Lutron LM-8000 microclimate recorder was used to record wind speed and direction at a height of 1.5m in real time in six residential communities in different locations in the downtown area of Zhengzhou.The way to record the wind direction is to manually observe the direction of the wind speed bar.?The experimental instrument(RR-9150 five-element weather station)was set in different green spaces on the campus of Henan Agricultural University.The test height was set at the height of 1.5m where the human body was most sensitive to temperature and humidity,and the wind speeds and wind direction at the three measuring points were recorded at the same time.The recording frequency is 10 minutes,and the recording time is from September 2016 to January 2017.After the records are completed,the data is collated and analyzed using Microsoft Excle 2010 and SPSS 19.0.Three parts of the numerical simulation were performed using ENVI-met software:?Simulation of wind environment in high-rise residential communities;?Changes in wind environment before and after planting structure in different layouts of green space;?The multi-story residential area has been optimized using wind environment simulation method.(1)Through the analysis of the wind environment in different communities from different perspectives,the characteristics of the wind environment in each community are summarized as follows: In the district with multi-layered structure of determinants,the change of wind speed and direction in each area is basically the same;while the change trend of wind environment in the high-rise building area is significant.The wind speed was enhanced due to the existence of “narrow tube effect” in high-rise buildings.The distance between the residential area and the city center is one of the important factors that affect the wind environment in the residential area.The wind direction in the residential area is mainly affected by the layout of the building and the direction of the surrounding roads,and the frequency of the calm wind is related to the degree of enclosing.(2)In the open space,the wind direction changes most frequently,and the wind speed and direction change greatly,indicating that air turbulence exchanges are active and open spaces.Wind speed and direction are more affected by the layout of buildings and planting methods in the determinate space,and the exchange of air turbulence is weaker than that in open spaces.There is little or no temperature difference between different underlying surfaces in the enclosing green space at night,so there is an absolute calm state at night.(3)The impact of green plants on wind speed and wind direction is mainly reflected in three aspects: reducing wind speed,generating turbulence,and changing wind direction.The tall and dense trees mainly affect the wind environment at a height of 10 m,and have a clear effect on the purification of air.The low shrubs mainly affect the wind environment at a height of 1.5m,weakening the strong wind at the corner of the building and changing the flow of wind.The relationship between the distribution of wind speed and its plant distribution is obviously in different green spaces.The effect of plant species on wind speed is not the same,but is mainly manifested in blocking wind and generating turbulence to promote air flow in a small area.(4)Optimizing the design through the ENVI-met simulation wind environment is a feasible method.Comparing the simulation results: The planting of greenery plants in the plot is not as good as possible.If the planting is too close,it will impede the air flow,leaving the residential area in a calm state,which is not conducive to the renewal of air and the diffusion of pollutants.Improper collocation of plants in the space between buildings will create “canyon winds” and strong wind speeds will affect residents' outdoor activities.Reasonable plant layout based on the layout of the building and the direction of the road is crucial to creating a good wind environment in the residential area.