Numerical modelling of transient dispersion of air pollution in perpendicular urban street intersection with detail inclusion of traffic dynamics

journal article in Web of Science

en

In this study, the authors focus on the utilisation of computer modelling for the detailed identification of transient pollutants dispersion in an ideal perpendicular intersection equipped with traffic lights. The attention is drawn to the dispersion of general passive scalar (density and diffusivity identical with air) in the ground level of the atmosphere. The modelled crossroad considers 2 lanes in each direction, in both street canyons. Sidewalks are located on either side of the road. The control points used to monitor air pollution are located on both sides of the road, in the middle of the sidewalk width, at the pedestrian head level (1.5 m above the sidewalk). Passenger cars are considered as the main source of the monitored air pollution in the intersection. Car movement is at the same time a major driving force affecting the air flow in the crossroad area. A model based on an Eulerian-Lagrangian approach to moving objects has been integrated into a commercial CFD software package called StarCD. The inclusion of traffic dynamics is a necessary step for a correct description of dispersion processes. The air pollution concentration fields were obtained from numerical predictions for traffic light switching periods of 60, 90, and 120 s. The correctness of the developed dispersion model was assessed on the base of NOX concentration measurements carried out in a real city intersection with similar geometry and corresponding traffic conditions as in the numerical model.

In this study, the authors focus on the utilisation of computer modelling for the detailed identification of transient pollutants dispersion in an ideal perpendicular intersection equipped with traffic lights. The attention is drawn to the dispersion of general passive scalar (density and diffusivity identical with air) in the ground level of the atmosphere. The modelled crossroad considers 2 lanes in each direction, in both street canyons. Sidewalks are located on either side of the road. The control points used to monitor air pollution are located on both sides of the road, in the middle of the sidewalk width, at the pedestrian head level (1.5 m above the sidewalk). Passenger cars are considered as the main source of the monitored air pollution in the intersection. Car movement is at the same time a major driving force affecting the air flow in the crossroad area. A model based on an Eulerian-Lagrangian approach to moving objects has been integrated into a commercial CFD software package called StarCD. The inclusion of traffic dynamics is a necessary step for a correct description of dispersion processes. The air pollution concentration fields were obtained from numerical predictions for traffic light switching periods of 60, 90, and 120 s. The correctness of the developed dispersion model was assessed on the base of NOX concentration measurements carried out in a real city intersection with similar geometry and corresponding traffic conditions as in the numerical model.

air pollution, intersection, CFD modelling, car, traffic lights

27.08.2019

Inderscience Enterprises Ltd.

0957-4352

65

1/2/3

71–83

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