Wind tunnel experiment of wind-induced single-sided ventilation under generic sheltered urban area

Abstract

Natural ventilation is an important ventilation method due to its potential to improve indoor air quality and provide an acceptable thermal environment without energy consumption. In the urban area, the ventilation performance of the natural ventilation is very sensitive to surrounding building density. This paper presents a wind tunnel experiment to assess the influence of urban density on the ventilation rate of single-sided ventilation. Spacing density, wind direction, and the number of openings were factors that were investigated in this experiment. The ventilation rate is evaluated by a continuous dose method of the tracer gas technique. The wind pressure coefficient at openings of the sealed model without openings was measured by pressure transducers. The streamwise velocity at the street canyon was measured by a split-film probe with a constant temperature anemometer unit. The ventilation rate, wind pressure coefficient fluctuations and velocity of an isolated building are compared to those of a building with two layers of surrounding buildings with the spacing of 0.5H (H is building height), 1H and 1.5H. A higher building density decreases the ventilation performance of windward opening cases and increases the ventilation performance of the leeward opening cases. The simplified ventilation rate prediction methods for wind-induced ventilation are presented.