In this paper, pollutant dispersion from point source was investigated numerically in an urban area. Numerical simulations were carried out using Computational Fluid Dynamics (CFD) models. The CFD models used for the simulation were based on the steadystate Reynolds-Average Navier-Stoke equations (RANS) with κ-ε turbulence models. A gas pollutant was emitted from a point source within the wake ...

OBJECTIVE The construction of a new road tunnel in Sydney, Australia, and concomitant reduction in traffic on a major road presented the opportunity to study the effects of this traffic intervention on respiratory health. METHODS We made measurements in a cohort of residents in the year before the tunnel opened (2006) and in each of two years afterwards (2007-2008). Cohort members resided in ...

Results are presented from wind tunnel simulations of gaseous pollutant dispersion in the atmospheric convective boundary layer (CBL) capped by a temperature inversion. The experiments were performed in the thermally stratified wind tunnel of the University of Karlsruhe, Germany. In the tunnel, the case of horizontally evolving, sheared CBL is reproduced. This distinguishes the employed experim...

Flow and traffic-originated pollutant dispersion in an urban street canyon with avenue-like tree planting have been studied by means of wind tunnel and CFD investigations. The study comprises tree planting of different crown porosity, planted in two rows within a canyon of street width to building height ratio W/H = 2 and street length to building height ratio L/H = 10 exposed to a perpendicula...

The aim of this study is to investigate the problems caused by discharge of polluted air from tunnels into the environment with a specific focus on residential areas. In city tunnels, portal or stacks, pollutant management is a big challenge. Nowadays, air quality management, particularly in urban tunnels, is considered as a part of the ventilation system design. The goal is to see the environm...

This article is the second in a two-paper series presenting results from wind tunnel and computational fluid dynamics (CFD) simulations of flow and dispersion in an idealized model urban neighborhood. Pollutant dispersion results are presented and discussed for a model neighborhood that was characterized by regular city blocks of three-story row houses with a single 12-story tower located at th...

Despite the improvement made in controlling local air pollution, urban areas are undergoing increasing environmental pressures and poor air quality is one of the major concerns. Recently, much attention has focused on the relationship between urban form and sustainability. There are indications that the density and the overall shape of cities can have implications on street level ventilation an...

The study of the effect of obstacles on flow and dispersion in the atmospheric boundary layer is one of the most important topics in atmospheric dispersion research. Computational Fluid Dynamics (CFD) methods are increasingly used to predict concentration fields near buildings in an operational context, but extensive validations are still needed. In this paper, we analyse the effect on flow and...

CFD simulation is used to predict 3D flow inside different configurations. Tunnel ventilation system is one example of CFD application field. Ventilation system is important in all kind of tunnels, road tunnel, rail tunnel or waterway tunnel. In all case CFD is able to predict chronic pollutant dispersion or accidental consequences. This paper presents the model of a waterway tunnel in France i...

Wind tunnel testing using reduced scale topography models is a mature technique [1] that enables the investigation of various aspects of wind flows from pollutant dispersion [2] to wind field modifications [3] affected by terrain. Alternatively, or in conjunction with a wind tunnel study, a rigorously developed computational technique would have the potential to provide additional and useful in...