Flow and dispersion in street intersections

Soulhac, Lionel; Garbero, Valeria; Salizzoni, Pietro; Méjean, P.; Perkins, Richard J.

doi:10.1016/j.atmosenv.2009.02.061

Cited by 105 publications

(63 citation statements)

References 15 publications

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“…On the contrary, flow instabilities and threedimensional effects within the intersection (see also Carpentieri et al, 2009) resulted in about 13% of the incoming mean flux from Gloucester Place continuing along that street, north of the intersection. This feature is not necessarily observed in more regular street canyon intersections (Soulhac et al, 2009) and should be taken into account by street intersection dispersion models. Many regulatory models neglect any interactions of the type found here and simply add the contributions from the two streets forming the intersection, thus neglecting the 85% of the flux from Gloucester Place that transfers into Marylebone Road (east) and the 50% of the flux from Marylebone Road into Gloucester Place (north) and, therefore, failing to provide a realistic prediction of concentration levels.…”

Section: Discussionmentioning

confidence: 99%

Tracer Flux Balance at an Urban Canyon Intersection

Carpentieri

Robins

2010

Boundary-Layer Meteorol

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Despite their importance for pollutant dispersion in urban areas, the special features of dispersion at street intersections are rarely taken into account by operational air quality models. Several previous studies have demonstrated the complex flow patterns that occur at street intersections, even with simple geometry. This study presents results from wind tunnel experiments on a reduced scale model of a complex but realistic urban intersection, located in central London. Tracer concentration measurements were used to derive threedimensional maps of the concentration field within the intersection. In combination with a previous study (Carpentieri et al., Boundary-Layer Meteorol. 133:277-296) where the velocity field was measured in the same model, a methodology for the calculation of the mean tracer flux balance at the intersection was developed and applied. The calculation highlighted several limitations of current state-of-the-art canyon dispersion models, arising mainly from the complex geometry of the intersection. Despite its limitations, the proposed methodology could be further developed in order to derive, assess and implement street intersection dispersion models for complex urban areas.

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Section: Discussionmentioning

confidence: 99%

Tracer Flux Balance at an Urban Canyon Intersection

Carpentieri

Robins

2010

Boundary-Layer Meteorol

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“…Characteristics of the transport pollution within the street intersection can be found in recent works [4][5][6]. Understanding processes of pollution transport in complex urban areas is important for estimation of ventilation intensity in the polluted street canyons, for finding suitable configuration of built-up areas and for developing local scale dispersion models.…”

Section: Introductionmentioning

confidence: 99%

Quadrant analysis of turbulent pollution flux above the modelled street intersection

Kukačka

Nosek²,

Kellnerová³

et al. 2013

EPJ Web of Conferences

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Abstract. The objective of this experimental study is to determine processes of a vertical turbulent pollution transport above the X-shaped street intersection in an idealised symmetric urban area for several approach flow directions. An experimental set-up for simultaneous measurement of the flow velocity and the tracer gas concentration in a high temporal resolution is assembled. Vertical turbulent scalar fluxes are computed from the measured data in a horizontal plane above the street intersection. The quadrant analysis was applied to the vertical turbulent pollution fluxes data. Events with dominant contribution to vertical turbulent pollution flux were detected. The mean duration, repetition frequency and the duration percentage were computed for these events. A strong influence of the approach flow direction on the the type of dominant events and their characteristics was resolved.

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“…• the advective fluxes along the street axes which produce the channeling of pollutant along directions not generally parallel to the external wind direction (Soulhac et al, 2009);…”

Section: Introductionmentioning

confidence: 99%

“…The exchange process within an intersection is simulated by an empirically based algorithm (Soulhac et al, 2009) that computes the partition of the mass fluxes along the street segments as a function of the geometry of the intersection, the external wind direction and σ φ , the standard deviation of the external wind direction fluctuations. The parameter σ φ is estimated by similarity relations as a function on the external boundary layer conditions.…”

Section: Introductionmentioning

confidence: 99%