Analysis of pollutant dispersion in an urban street canyon

Results are presented from a scries of wind tunnel tests to measure the cavity pressure dynamics of a flexible roofed building with a single dominant opening. Tests were conducted in a simulated atmospheric boundary layer, representative of an open-country terrain, for the model configured with five different roof tensions, three internal volumes, two windspeeds and five opening azimuth angles. The ratio of air-to-building bulk moduli was used as a measure of roof tension and buildings with 0.02 < Ka/Kb < 7.5 were tested. It was found that the cavity scaling parameter (Eq. (1)) provided a convenient means of collapsing the unsteady cavity pressure data for those configurations where significant resonance occurred. A flow component into the opening was necessary to sustain large resonant oscillations and this occurred with an opening on both windward and leeward sides of the building. Increased flexibility of the roof membrane reduced the value of the Helmholtz frequency and also reduced the magnitude of the resonant response. © 1999 Elsevier Science Ltd. All rights reserved.