Revisiting the 'Venturi effect' in passage ventilation between two non-parallel buildings
2015 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 94, 714-722 p.Article in journal (Refereed) PublishedText
A recent study conducted by Blocken et al. (Numerical study on the existence of the Venturi effect in passages between perpendicular buildings. Journal of Engineering Mechanics, 2008, 134: 1021-1028) challenged the popular view of the existence of the 'Venturi effect' in building passages as the wind is exposed to an open boundary. The present research extends the work of Blocken et al. (2008a) into a more general setup with the building orientation varying from 0 degrees to 180 degrees using CFD simulations. Our results reveal that the passage flow is mainly determined by the combination of corner streams. It is also shown that converging passages have a higher wind-blocking effect compared to diverging passages, explained by a lower wind speed and higher drag coefficient. Fluxes on the top plane of the passage volume reverse from outflow to inflow in the cases of alpha = 135 degrees, 150 degrees and 165 degrees. A simple mathematical expression to explain the relationship between the flux ratio and the geometric parameters has been developed to aid wind design in an urban neighborhood. In addition, a converging passage with a = 15 is recommended for urban wind design in cold and temperate climates since the passage flow changes smoothly and a relatively lower wind speed is expected compared with that where there are no buildings. While for the high-density urban area in (sub)tropical climates such as Hong Kong where there is a desire for more wind, a diverging passage with alpha = 150 degrees is a better choice to promote ventilation at the pedestrian level.
Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 94, 714-722 p.
Urban wind, Ventilation, Pedestrian wind comfort, Building passage
IdentifiersURN: urn:nbn:se:kth:diva-181387DOI: 10.1016/j.buildenv.2015.10.023ISI: 000367759400023ScopusID: 2-s2.0-84947288768OAI: oai:DiVA.org:kth-181387DiVA: diva2:901748
QC 201602092016-02-092016-02-012016-02-09Bibliographically approved