Original scientific paper
THE EFFECT OF SOURCE TREATMENT ON POLLUTANT DISPERSION IN AN IDEALISED URBAN ROUGHNESS IN NUMERICAL SIMULATIONS USING THE STANDARD k-ε TURBULENCE CLOSURE MODEL
Fotios Barmpas
; Laboratory of Heat Transfer and Environmental Engineering, Aristotle University Thessaloniki, Greece
Ioannis Ossanlis
; Laboratory of Heat Transfer and Environmental Engineering, Aristotle University Thessaloniki, Greece
Nikolas Moussiopoulos
; Laboratory of Heat Transfer and Environmental Engineering, Aristotle University Thessaloniki, Greece
Abstract
The need for accurate model predictions in urban air quality assessment studies during the past decade has led to the ever
increasing use of Computational Fluid Dynamics (CFD) models in order to resolve the various local scale inhomogeneities which
dominate flow and dispersion and are usually encountered in urban areas. Towards the aim of improving model predicted dispersion
via the use of CFD models, a numerical study was undertaken in order to investigate the effect of different techniques applied for
treating the sources of emissions on the near source behaviour of the models, as well as on the actual predicted concentrations at
locations away from the vicinity of the sources under consideration. A series of 3D numerical simulations were performed for the
wind tunnel model geometry of the Mock Urban Setting Test (MUST) field experiment of the University of Hamburg, Meteorological Institute, Division of Technical Meteorology, which was made available within the frame of COST Action 732. Overall in conclusion, results show that depending on the type of source, the intensity of the vertical component of the emissions exit velocity at the source and the mesh refinement close to source boundaries predicted concentrations can deviate significantly from the wind tunnel measurements. However, it is possible to partially improve the performance of a CFD model in urban dispersion problems, mainly via the application of the proper combination of these parameters.
Keywords
Source treatment; exit velocity; pollutant dispersion; roughness; turbulence
Hrčak ID:
64342
URI
Publication date:
12.12.2008.
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