期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 851, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2022.158053
关键词
Far-field pollutants; Air exchange rate (AER); Atmospheric dispersion factor (ADF); Multi-component ventilation performance; Urban canopy layer (UCL)
资金
- Science and Technology Innovation Program of Hunan Province [2020RC4032]
- Hunan University of Technology
- Provincial Key R &D Program of Hunan [2022SK2 084]
- Wuhan Application Foundation and Cuttingedge Research Plan [2020010601012206]
- Wuhan University Specific Fund [WHU-GJZDZX-PT08]
- Natural Science Foundation of China (NSFC) [51778504, U1867221]
This study conducted a delicate CFD research on a multi-street canyon model with varying thermal stratifications and non-uniformities of buildings. The findings indicated significant influences of ground heating intensity and building unevenness on canyon ventilation and pollution dispersion, providing theoretical reference for urban design in compact cities.
In the present work, a delicate CFD research of a multi-street canyon model with varying thermal stratifications and non-uniformities of buildings was conducted to investigate the street ventilation and pollutant dispersion between the compact urban blocks. Non-isothermal turbulent wind flow, temperature field and pollutant dispersion in a two-dimensional computational domain were solved by the Renormalization Group (RNG) k-epsilon turbulence model along with the enhanced wall treatment. Present numerical results indicated that the variation of ground heating intensity has a significant influence on the airflow pattern in the step-down case, and the distribution of pollutants in the street canyons mainly depends on the variation of the upper clockwise vortex. The canyon ventilation performance became better as the unstable thermal stratification strengthened. Similarly, the increase of ground heating intensity could re-duce ADF (atmospheric dispersion factor) in the step-down case and ADF became the lowest when Ri = -3.92 was maintained. Additionally, the increase of building unevenness further complicated the canyon airflow structure, which aggravated the pollution of the canyon. In the step-down configuration, as the standard deviation of adjacent building height gradually increases, canyon ventilation could be further enhanced. For the step-up configuration, the best ventilation performance was found at & USigma;H = 16.7 %. ADF of adjacent canyons also varied greatly. When & USigma;H = 33.3 % was maintained, the peak and bottom values of ADF were discovered in the step-up and step-down cases, respectively. Present research has provided a theoretical reference for guiding urban design and improve living environment in modern compact cities.
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