On the heating environment in street canyon

Abstract

This study investigates the impact of building aspect ratio (building-height-to-street-canyon-width-ratio), wind speed and surface and air-temperature difference (Δθs-a) on the heating environment within street canyon. The Reynolds-averaged Navier-Stokes (RANS) and energy transport equations were solved with Renormalization group (RNG) theory version of k-turbulence model. The validation process demonstrated that the model could be trusted for simulating air-temperature and velocity trends. The temperature and velocity patterns were discussed in idealized street canyons of different aspect ratios (0.5-2.0) with varying ambient wind speeds (0.5-1.5 m/s) and Δθs-a (2-8 K). Results show that air-temperatures are directly proportional to bulk Richardson number (Rb) for all but ground heating situation. Conversely, air-temperatures increase significantly across the street canyon with a decrease in ambient wind speed; however, the impact of Δθs-a was negligible. Clearly, ambient wind speed decreases significantly as it passes over higher AR street canyons. Notably, air-temperatures were the highest when the windward wall was heated and the least during ground heating. Conversely, air-temperatures were lower along the windward side but higher within the street canyon when the windward wall was heated. © 2010 The Author(s).