Details
| Original language | English |
|---|---|
| Pages (from-to) | 202-227 |
| Number of pages | 26 |
| Journal | Urban Climate |
| Volume | 20 |
| Publication status | Published - Jun 2017 |
Abstract
This study investigates ventilation performance in parametric urban scenarios using a large-eddy simulation (LES) model called the Parallelized LES Model (PALM). With various combinations of planning parameters, air flows and pedestrian-level velocity ratios in a total of 48 scenarios are investigated. Major findings and recommendations are: First, ground coverage ratio (λp) is the most important factor for good ventilation. Second, in cases of homogeneous building heights, a power regression between velocity ratios and aspect ratios of parallel street canyons can be derived, which suggests that good understanding of local microclimate, especially prevailing wind directions in summer, is needed in urban planning. Third, the effects of building height differentials on urban ventilation are connected to urban density. In low-density scenarios, inhomogeneous building heights give worse ventilation performance compared to homogeneous cases. In high-density scenarios, inhomogeneous building heights result in better ventilation performance than homogeneous cases. Inhomogeneous building heights generate more vertical momentum fluxes in street canyons and have a negative (positive) effect on velocity ratios of low-density (high-density) parametric urban fabrics. The application of this point is that homogeneous building heights are recommended when low density is present, and inhomogeneous building heights may be better in cases of high density.
Keywords
- Air ventilation assessment (AVA), High-density city design, Large-eddy simulation (LES), Urban morphology, Velocity ratio
ASJC Scopus subject areas
- Social Sciences(all)
- Geography, Planning and Development
- Environmental Science(all)
- Environmental Science (miscellaneous)
- Social Sciences(all)
- Urban Studies
- Earth and Planetary Sciences(all)
- Atmospheric Science
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In: Urban Climate, Vol. 20, 06.2017, p. 202-227.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Large-eddy simulations of ventilation for thermal comfort — A parametric study of generic urban configurations with perpendicular approaching winds
AU - Wang, Weiwen
AU - Ng, Edward
AU - Yuan, Chao
AU - Raasch, Siegfried
N1 - Publisher Copyright: © 2017 Elsevier B.V. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/6
Y1 - 2017/6
N2 - This study investigates ventilation performance in parametric urban scenarios using a large-eddy simulation (LES) model called the Parallelized LES Model (PALM). With various combinations of planning parameters, air flows and pedestrian-level velocity ratios in a total of 48 scenarios are investigated. Major findings and recommendations are: First, ground coverage ratio (λp) is the most important factor for good ventilation. Second, in cases of homogeneous building heights, a power regression between velocity ratios and aspect ratios of parallel street canyons can be derived, which suggests that good understanding of local microclimate, especially prevailing wind directions in summer, is needed in urban planning. Third, the effects of building height differentials on urban ventilation are connected to urban density. In low-density scenarios, inhomogeneous building heights give worse ventilation performance compared to homogeneous cases. In high-density scenarios, inhomogeneous building heights result in better ventilation performance than homogeneous cases. Inhomogeneous building heights generate more vertical momentum fluxes in street canyons and have a negative (positive) effect on velocity ratios of low-density (high-density) parametric urban fabrics. The application of this point is that homogeneous building heights are recommended when low density is present, and inhomogeneous building heights may be better in cases of high density.
AB - This study investigates ventilation performance in parametric urban scenarios using a large-eddy simulation (LES) model called the Parallelized LES Model (PALM). With various combinations of planning parameters, air flows and pedestrian-level velocity ratios in a total of 48 scenarios are investigated. Major findings and recommendations are: First, ground coverage ratio (λp) is the most important factor for good ventilation. Second, in cases of homogeneous building heights, a power regression between velocity ratios and aspect ratios of parallel street canyons can be derived, which suggests that good understanding of local microclimate, especially prevailing wind directions in summer, is needed in urban planning. Third, the effects of building height differentials on urban ventilation are connected to urban density. In low-density scenarios, inhomogeneous building heights give worse ventilation performance compared to homogeneous cases. In high-density scenarios, inhomogeneous building heights result in better ventilation performance than homogeneous cases. Inhomogeneous building heights generate more vertical momentum fluxes in street canyons and have a negative (positive) effect on velocity ratios of low-density (high-density) parametric urban fabrics. The application of this point is that homogeneous building heights are recommended when low density is present, and inhomogeneous building heights may be better in cases of high density.
KW - Air ventilation assessment (AVA)
KW - High-density city design
KW - Large-eddy simulation (LES)
KW - Urban morphology
KW - Velocity ratio
UR - http://www.scopus.com/inward/record.url?scp=85017216262&partnerID=8YFLogxK
U2 - 10.1016/j.uclim.2017.04.007
DO - 10.1016/j.uclim.2017.04.007
M3 - Article
AN - SCOPUS:85017216262
VL - 20
SP - 202
EP - 227
JO - Urban Climate
JF - Urban Climate
SN - 2212-0955
ER -