Abstract
Air pollution, both gaseous and in the form of dust, is a problem that affects numerous densely built-up areas of modern cities. Based on this assumption, the authors of the following paper have examined an exemplary part of urban space with various building developments located in Warsaw downtown. Both experimental and numerical studies were conducted for the two prevailing wind directions observed in this area, that is the west wind and the south-west wind.
Experimental research was conducted with the application of two known laboratory techniques, i.e., the oil visualization method and the sand erosion technique. The studies were conducted in an open-circuit wind tunnel. Commercial ANSYS Fluent program was used for numerical simulations. The k-ε realizable turbulence model, often applied for this type of tasks, was used in the calculations. As a result, distributions of the velocity amplification coefficient were obtained in the area under consideration, as well as images that present the averaged airflow direction. On basis thereof, potential zones where contamination accumulation may occur were determined.
The impact that introduction of a hypothetical high-rise building into the area would exert on wind conditions in its vicinity was also tested. High-rise buildings tend to intensify airflow in their immediate vicinity. Thus, they can improve ventilation conditions of nearby streets. However, in this particular case, the research prompted the conclusion that the proposed building causes turbulence and increased velocity gradients in the majority of elevation planes. On the other hand, in the ground-level zone, the building blocks rather than intensifies the airflow.