Research On Pedestrian Wind Comfort In Urban Riverside Area

Outdoor wind environment is an important factor affecting pedestrian comfort.The intensive development of cities makes the problem of wind environment in urban areas increasingly prominent.As the core area of the city’s development,riverside area often integrates the comprehensive functions of transportation,commerce,life,tourism,cultural landscape and so on,with intensive internal personnel flow.The research on pedestrian wind comfort in this area plays an important role in the construction of traffic environment and ecological livable city in the national green development strategy.However,due to the influence of spatial form and land-water thermal difference,the wind environment in urban riverside area has local characteristics,and the regional wind environment is different from the overall urban wind environment.It is urgent to construct the research method of local wind field characteristics in urban riverside area,put forward scientific improvement strategy,and form a pedestrian wind comfort evaluation and improvement standard.The main work of this paper is as follows:(1)Proposing the research method of local wind field characteristics in urban riverside.It is found that there is a deviation between the measured meteorological data in the riverside area and the data recorded by the meteorological station,and the causes is analyzed.The hourly anomaly wind speed method and the CFD method is used to study the influence of local circulation and urban spatial form on the local wind field in the riverside area,and the site is finely modeled,through numerical simulation,the wind speed ratio of the measuring points in the study area under 16 wind directions is obtained.According to the conversion relationship of exponential wind and the wind speed ratio,the corresponding relationship between the meteorological station and the wind environment data in the study area under the combined action of land-river wind is established.The application in the riverside area of Changsha shows that: land-river wind occurs in varying degrees in each season,and the maximum hourly anomaly wind speed reaches 1.35m/s,which has an important impact on the local wind field.The numerical calculation of local wind field characteristics in the riverside area was carried out,the continuous wind environment data in the study area was obtained,and the reliability of the calculation results was verified by actual measurement.(2)Proposing the evaluation method of urban pedestrian wind comfort based on local correction of UTCI index.From the perspective of dynamic effect of wind on pedestrians,an evaluation method of pedestrian wind comfort under the combined action of land-river wind is proposed.Considering the thermal effect and dynamic effect of wind on pedestrian,16 kinds of relationship of wind comfort under the coupling of wind dual effect are established.By means of field measurement and questionnaire survey,this paper studies the perceived differences of comfort among regional people living in specific environment all year round,and puts forward the local correction method of UTCI thermal comfort index.Taking Changsha as an example,the research shows that:the scale of "no heat stress" of UTCI index in Changsha increases to[+15.4,+32.4],it is because that people live in a specific environment all year round,and their resistance to the hot climate is enhanced,while they are sensitive to the wet and cold climate.According to 16 kinds of relational formula,the evaluation index of urban pedestrian wind comfort in Changsha was established.(3)Proposing the improvement method of pedestrian wind comfort in urban riverside area.Based on the scientific garden design theory under the landscape architecture,this paper puts forward a method to improve the wind comfort of pedestrian by using the wind resistance of garden plants and the microclimate regulation function of landscape fog spray.Research shows: the combined row planting form of trees and shrubs takes into account the advantages of tree row planting and shrub row planting,and its wind resistance performance is the best,the landscape fog spray adopts the intermittent opening and closing mode every 30 minutes,which is conducive to the decline of local temperature.The experiment of improving the adverse wind environment in the riverside research area of Changsha was carried out to verify the effectiveness of the method.(4)Establishing the evaluation standard of pedestrian wind comfort in urban riverside area.According to PDCA management mode,the evaluation standard is established,the method of comprehensive weight coefficient evaluation through 6 kinds of scoring item indexes and 1 kind of additional scoring item indexes is proposed,and a workflow of wind environment analysis and improved in urban riverside area is formed.According to the standard,we evaluated and improved the pedestrian wind comfort in the Pearl River research area of Guangzhou,and verified the applicability of the standard.Finally,the evaluation results of Changsha riverside area which in hot summer and cold winter area and Guangzhou riverside area which in hot summer and warm winter area were compared to analyze the impact of climate on pedestrian wind comfort.There are 62 figures,45 tables and 151 references.