LABORATORY STUDY OF CONVECTIVE CIRCULATION OVER URBAN ROUGHNESS

The results of experimental study of the large-scale convective circulation over the flat surface and city layout, produced by extended localized heater for different heating intensity, are presented. The structure of the flow for these configurations, the mean, and pulsation characteristics were analyzed and compared. It is shown that urban roughness suppresses the large-scale circulation, which is mainly located above the urban terrain. The urban terrain leads to noticeable spatial non-homogeneity of the main circulation but velocity fluctuations are relatively low and do not exceed 5%. It is shown that a tall building can provide intensive fluctuations due to flow instability similar to the flow behind a bluff body. Correlation analysis shows significant correlation between terrain elevation and horizontal velocity. The correlation between velocity and building height is low.