Środowiskowe Seminarium Fizyki Atmosfery

Wind tunnel experiments and numerical modelling constitute basic research tools in studying flows within urban structure. Numerical models are now used to address a broad range of practical issues, such as: predicting the influence of urban development on urban climate, diffusion of atmospheric pollution in cities, developing emergency response systems, building aeroelasticity.We shall present the current status of developing the infrastucture of urban fluid dynamics and preliminary results obtained with its use. An automated process of constructing the representation of a detailed structure of buildings will be presented along with an example of application to a tall building of a complex shape, located in the city of Warsaw.We shall also discuss results of a series of idealized numerical experiments reflecting the influence on static stability on the flow structure. The results gained so far exhibit flow structures identified in early wind tunnel studies, such as a recirculation zone in the lee side of a building and a horseshoe vortex in a horizontal plane near the surface. Numerical experiments show that the extent of the lee vortex and the location of the flow stagnation zone near the ground do not depend noticeably onstability. However, with growing stability a secondary horseshoe vortex arises aloft; to our knowledge, this feature has not yet been documented in the literature.Michał Korycki, Lech Łobocki, Andrzej Wyszogrodzki