Modeling City Patterns for Urban Ventilation: Strategies in High Density Areas of Singapore
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Effective urban ventilation cools physical surfaces, reduces energy consumption and improves human thermal comfort under hot conditions, especially in tropical and subtropical regions. It is important for planners and architects to understand the influences of urban morphological features on wind environment and air movement.
In addition to a concise literature review regarding wind behaviour in tropical and subtropical high-density urban environments, this study uses Computational Fluid Dynamics (CFD) simulations to assess strategies of adjusting breezeway features based on Singapore’s climate. These strategies include: (1) reducing breezeway network densities; (2) varying breezeway widths; (3) varying breezeway spacing; (4) staggering the block; and (5) inserting T-shaped junctions by merging two plots. They were studied in two plot types, namely, separate blocks on top of the podium (type A) or ground (type B), which have the same building plot ratios and site areas.
By comparing strategies, in general, the second strategy—varying breezeway widths—achieves the best compromise between pedestrian and building ventilation potentials. On the contrary, the third and fourth strategies lead to poor ventilation. In addition, by comparing the plot types, type B (without podium) tends to achieve better wind environments in most of the strategies. Furthermore, with higher design flexibility, breezeway patterns inside land lots have stronger effects on urban ventilation than breezeway patterns outside land lots.
The results in terms of the influence of breezeway network patterns as a design parameter are significant for both planners and architects. For planners, they provide direct guidance for arranging streets and other city open spaces, which should be planned prior to building design. For architects, they offer an effective way to parameterise the building layouts especially those of extreme complexity. Whilst the study focuses on the macro level, both aspects of urban planning and design are important complements to other urban cooling strategies.
KeywordsUrban ventilation Breezeway network pattern High density CFD Passive cooling Singapore
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