| The rapid urbanization has brought about a expansion of urban space,the varied terrain of Chongqing,and the intensive urban construction,resulting in a quiet wind environment inside the urban area,and has caused problems such as pollutant accumulation and urban heat islands.As one of the important elements of urban microclimate,wind is strongly related to space,and the impact of urban spatial morphology on the ventilation environment should be fully improved.The green space of the pedestrian street is an important part of the public activity space system,which undertakes most of the outdoor communication activities of the citizens.Existing pedestrian street green spaces are often designed based on past experience,and there are few studies and designs for analyzing and creating microclimates in green spaces.In this study,from the perspective of creating a good street ventilation environment,through the combination of measured research and simulation research,the street green space is targeted for optimization and layout design.The content of the article is mainly composed of the following parts:First,analyze the impact of green space on the street ventilation environment,and construct an evaluation method of the ventilation environment.Through combing relevant literature at home and abroad,the research integrates the relevant conclusions of wind tunnel experiment,computer simulation and field measurement,establishes the development level and theoretical support of the research,and further implements the research focus on this basis.Based on the overall ventilation performance of the street and the distribution characteristics of the wind environment inside the green space,the study constructed an evaluation method to reflect the space wind environment with the wind speed ratio and the static wind rate.Secondly,empirically study regional wind environment issues,and determine the direction of wind environment optimization through street feature analysis.The study screened out six representative green spaces of pedestrian streets in Chongqing,recorded the climate and environment of the streets,and concluded the overall impact of the green spaces on the wind environment.At the same time,it also found a negative street pollution level and wind speed ratio.The correlation trend and the positive correlation trend with the static wind rate prove the actual influence relationship of the green space pattern-wind environment-pollutant concentration,and provide data support for the subsequent simulation experiments.Based on the statistical analysis of the street crowd activities,the six pedestrian street spaces are divided into three different types,and the optimization focus directions of the three types of street wind environment are analyzed and studied.Again,combined with the simulation study of the measured data calibration,based on the assessment of the ventilation environment to explore the impact of changes in the greening layout.Simulate and analyze the measured green space of six pedestrian streets to verify the feasibility of the simulation method,and evaluate the actual layout of the six types of tree arrays based on the static wind rate and wind speed ratio.The small-scale tree green space with the smallest wind environment impact and continuous sides has the greatest impact on the street wind environment,and the medium-sized tree tree array with separate sides is more advantageous in traffic streets,and the central continuous large tree space is in open streets Has an advantage.Analyze the relationship between the wind environment and the greening layout,mainly including:（1）The layout of the tree array that is most conducive to street permeability is often located on the edge of the street,including a single row on the lee side,and a double-row arrangement near the sides of the street;（2）The layout form most conducive to reducing the quiet wind area of ??the green space is often located in the center of the street,including the central single row and the central double row arrangement;（3）The number of tree arrays arranged more than three rows will have a greater negative effect on the street ventilation performance Impact;（4）In the vertical separation of the tree array,the green space with a separation distance of more than 5 meters can effectively reduce the wind shadow area between the tree arrays;（5）In the choice of tree types,small trees are most beneficial to enhance the street The overall ventilation environment,large trees can effectively reduce the quiet wind area under the tree.Finally,the street greening design ideas are summarized,and the ventilation optimization strategies of different street greening spaces are proposed.Analyze and study the greening design methods of the three types of street spaces,and put forward strategies for optimizing the wind environment of the current street greening spaces,clarify the areas that need to be focused on and improve,and optimize the greening layout of the streets to improve the wind in public places with concentrated crowd The environment enhances the ability of street pollutants to diffuse.Based on the results of this study,we discuss the relevant revelation of green space planning and design. |
