The importance of local winds for the aerationof urban areas having hot and windless climatic conditions

Introduction. A city with its high-rise buildings, greenery and landscaping that prevent air motion aggravate windless conditions typical for climates in the cities located in the southern latitudes characterized by heat and lack of wind. Urban built-up areas have stagnant and overheated air that causes sultriness and significant air pollutions caused by anthropogenic sources. These factors require systematization of the local aerodynamics by means of local wind generation using solar energy. Materials and methods. Methods of theoretical research, large-scale field measurements involving the use of instruments, visual observations by means of smoke screening of the urban area’s structure were applied and laboratory research into thermal and wind processes using physical models of cities were applied to identify the role of insolation in the generation of local thermal winds that improve the local environment on the micro- and macroscale. Results. The author has found that if built-up urban areas have no general circulation wind fields, urban aeration systems develop local independent air flows due to the temperature difference between heat and cool islands. The temperature difference was applied as the source material for an urban wind model and it also helped to identify the dependence of the local wind velocity on the thermal contrast of urban islands. A classification of aeration models is developed at macro; meso-; micro- and nanoscales. Conclusions. The practical area of application of the theory of hot and windless processes was identified in respect of urban area planning. The aerodynamics of an urban environment was systematized due to the generation of local thermal winds. The process of local thermal wind generation was studied; the classification of natural aeration models was made for urban areas. Methods of using solar energy were applied to generate local winds, to develop the microclimate and to enhance the environment of urban areas and structures as a prerequisite for targeted urban planning actions, three-dimensional space-planning solutions that apply to urban structures, landscaping, architectural and structural concepts of buildings. Acknowledgments. The work was performed in accordance with the research schedule of Department of Design of Buildings and Structures, NRU MGSU, focused on “Function, Structure, Environment in the Architecture of Buildings and Towns”.