Wind tunnel experiment on high-buoyancy gas dispersion around isolated cubic building

• Published in: Journal of wind engineering and industrial aerodynamics Vol. 202; p. 104226
• Main Authors: Lin, Chao, Ooka, Ryozo, Kikumoto, Hideki, Sato, Taiki, Arai, Maiko
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2020
• Subjects: Building wake; High temperature; High-buoyancy gas; Pollutant dispersion; Wind tunnel experiment; High-buoyancy gas; Pollutant dispersion; Wind tunnel experiment; Building wake; High temperature
• ISSN: 0167-6105; 1872-8197
• DOI: 10.1016/j.jweia.2020.104226

It is important to evaluate environmental impact of exhaust gas with high temperature and high-concentration hazardous pollutants from emergency generators in the urban environment. In this study, we conducted wind tunnel experiment on high-buoyancy gas dispersion around an isolated cubic building. Experiments were conducted under three exhaust speed ratios to study their influence on pollutant dilution. Light and neutrally buoyant gases were used to conduct dispersion experiments under the same conditions. The concentration was measured in the vertical and horizontal planes in high resolution. We found that high buoyancy in the light gas and large exhaust momentum can prevent pollutants from getting trapped within the recirculation zone behind the building, resulting in a lower mean concentration. In addition, high buoyancy in diluting pollutants became effective when the exhaust ratio was higher. However, high buoyancy and a lower exhaust ratio may lead to a stronger concentration fluctuation. Moreover, a concentration time series revealed that near the leeward wall, concentration time variation depended majorly on the measured height and gas density. This study can help deepen our understanding of high-buoyancy gas dispersion, which is different from that of neutrally buoyant gas, and help us devise suitable countermeasures. •High-buoyancy gas is used to study exhaust gas dispersion from emergency generators.•Concentration distribution is measured in high-spatial resolution.•High buoyancy in diluting pollutant is more effective when exhaust ratio increases.•High buoyancy and low exhaust ratio lead to stronger concentration fluctuation.