Numerical simulation of pollutant dispersion around a building complex Mohamed Lateb a, * , Christian Masson a , Ted Stathopoulos b , Claude Bédard a a ÉTS (École de technologie supérieure), 1100 rue Notre-Dame Ouest, H3C 1K3 Montréal, Québec, Canada b Concordia University, 1455 de Maisonneuve Blvd. West, H3G 1M8 Montréal, Québec, Canada article info Article history: Received 3 December 2009 Received in revised form 28 January 2010 Accepted 9 February 2010 Keywords: Numerical simulation Computational fluid dynamics (CFD) Pollutant dispersion Atmospheric boundary layer (ABL) Realizable ke3 turbulence model abstract The dispersion of exhausted pollutants from a building roof stack situated in the wake of a neighbouring tower has been studied using computational fluid dynamics (CFD) with the realizable ke3 turbulence model for closure. Two scales are considered in this work, full-scale (1:1) and wind tunnel scale (1:200). Of primary interest are the distributions of the plume and of the pollutant concentrations on the building roof as well as on the leeward wall of the tower. Two stack heights and pollutant exhaust velocities have been considered for the distribution of pollutant concentrations in the neighbourhood of the building from which the pollutant is emitted. Results are compared with measurements from field and wind tunnel experiments to estimate the accuracy of simulations. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Increasing levels of pollution in urban environments has moti- vated the development of new techniques to model the dispersion of pollutants in the atmosphere. This topic is of special significance in urban areas as it is one of the significant sources of poor indoor air quality due to contamination of fresh air intakes. In the present study, the particular interest is in pollutant emissions from rooftop stacks and how the presence of the tower upstream the emitting building affects the distribution of pollutant concentrations around buildings. Current standards for building ventilation systems recommend that rooftop stacks be designed such that their emissions do not contaminate the fresh air intakes of the emitting or any nearby buildings. Several studies have been carried out on the dispersion of pollutants in urban environments, most of which considering a single building without neighbours. Of note are the works of Mavroidis et al. [1] who was interested in pollutant distributions around a cubic building with a transmitting continuous source of tracer gas, from different lateral and vertical positions; the research by Li and Meroney [2,3], who studied the concentration of exhausted pollutants from a building roof for different wind directions and stack positions; other works taking into account neighbouring structures have been carried out at wind tunnel scale. For instance, Stathopoulos et al. [4] studied pollutant concentration, on the roof and windward wall of a building, caused by a small roof stack emitting pollutants at various speeds. Yassin et al. [5] has reproduced a built-up area within a 500 m radius to study dispersion under various weather conditions. Some works have been directed at improving model parame- ters, such as the prescription of boundary conditions or wall functions, in order to better reproduce field measurements. Among them, the work of Liu et al. [6] focused on the use of two important parameters, namely roughness height and friction velocity, in establishing velocity and turbulence intensity profiles at the inlet of the domain. The work of Wang and Stathopoulos [7] considered the impact of roughness height upstream of the site and on the velocity profile at the domain inlet for homogeneous and inhomogeneous terrains. Finally, Wagaman et al. [8] carried out flow visualizations in the recirculation zones for two different building heights. The present study considers a building in the wake of another higher building located upstream. This research complements previous experimental works completed at Concordia University in the wind tunnel and at full-scale by applying numerical modeling techniques (Computational Fluid Dynamics e CFD). The aim is to numerically reproduce experimental works of Stathopoulos et al. [9], particularly the field experiments of August 12th and 26th, 2002. These experiments are simulated using the software Gambit 2.4.6 for the domain and mesh design, and Fluent 6.3.26 for the solution of the system of partial differential equations. Special attention is given to the analysis of the distribution of pollutant concentrations at various locations on the roof of the building compared to the site of the stack, while taking into account the * Corresponding author. E-mail address: mohamed.lateb@etsmtl.ca (M. Lateb). Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv 0360-1323/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.buildenv.2010.02.006 Building and Environment 45 (2010) 1788e1798