DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
An experimental investigation of the flow and transfer processes in homogeneous urban street-canyon geometries using Particle Image Velocimetry
Краткое описание
This paper examines the flow and exchange processes in a homogeneous urban geometry using Particle Image Velocimetry in order to deduce the breathability (or ventilation) capacity of the urban area. The urban geometries addressed have the form of regularly spaced street-canyon arrays of different packing densities, ranging from λp = 0.30 to 0.67, reflecting typical European and North-American cities. The flow measurements reveal that the dominant flow feature within the street canyon cavity is a recirculation cell, while vertical exchange processes (of volume flux and momentum flux) occurring at the building rooftop level. The exchanged flux at the building rooftop level was characterized and quantified by a mean exchange velocity in a similar fashion as in the concept of an entrainment velocity. The results show that normalised exchange velocity values (over the mean bulk velocity) for the most dense and sparse geometries differ by more than 80 %. Good agreement is found with previous work in a similar geometry, performed in a wind tunnel.