Simulation Of Urban Wind Field Based On GIS Rapid Modeling

Urban wind field plays an important role in quantitative assessment of urban environment which contributes to settle the dispersion of pollutant,pedestrian wind comfort,urban heat island and urban ventilation.It is one of the key issues in the study of urban microclimate.Nowadays,the development and maturity of Geographic Information System?GIS?makes it possible to study urban wind fields based on morphometric methods.Create Object ARX applications on the Integrated Development Environment Visual Studio with the purpose of secondary development of AutoCAD.Rapid batch modeling of large-scale urban complex,automatic recognition of terrain roughness and obtaining blockage ratio of urban complex under different wind direction can be implemented on acount of GIS.Based on morphometric methods,create Object ARX applications to extract z₀ and z_d of urban surfaces.Guiyuan station of meteorological bureau Shenzhen municipaity is taken as an example to determine spatial z₀ and z_d in 2 km upstream fetch on the strength of European Standard.Compared with Engineering Sciences Data Unit?ESDU?and Australian/New Zealand Standard?AS/NZS?.RT and Rau methods are closer to the specified value of urban.Gaining stationary wind records of Guiyuan and Pingan station,and taking Guiyuan station wind speeds as the reference wind speeds to predict approaching wind speed profiles and wind speed at Pingan with z₀ and z_d.Validation metrics are applied to quatify the impact of wind speeds,morphometric methods and wind speed profile on the predictions results.It demonstrates that predicted wind speeds which combines z₀ and z_d of Bot method and LOG wind speed profile are more reasonable than others under stationary and neutral atmospheric boundary condition.Niigata urban models in the benchmark tests of Architectural Institute of Japan will be taken as an example to evaluate of urban wind field,The transient simulation of Niigata is conducted which takes advantages of WALE LES and SST k-w DES,and then solution accuracy are validated by comparing simulation results with high quality measured data from wind tunnel.The results demonstrate that WALE LES is the most accurate and has more advantages of simulations the low wind speed area of the leeward side of the building in the wake.However,the high wind speed area caused by interference between buildings indicates are overpredicted.