INTERCOMPARISON OF NUMERICAL URBAN DISPERSION MODELS ―PART Ⅰ: STREET CANYON AND SINGLE BUILDING CONFIGURATIONS

摘要

Microscale Computational Fluid Dynamics (CFD) models have become an efficient and common simulation tool for assessment and prediction of air quality in urban areas. The proper validation of such a model is a crucial prerequisite for its practical application. Within the framework of the European research network TRAPOS a working group on computational fluid dynamics modelling was established and model intercomparison exercises were launched. Different Computational Fluid Dynamics Codes were applied for simulating the wind flow and pollutant concentration patterns in several test cases. The aim of the present model intercomparison is (1) to assess and allocate the source of differences that appear when different CFD codes using the same turbulence model are applied to well defined test cases and (2) to improve the knowledge base for model development and application. Throughout the series of model applications covering manifold urban configurations, the overall agreement between the various models and experimental data is fair. In spite of quantitative differences between the various numerical results, the models are capable of reproducing the flow patterns and dispersion characteristics observed in urban areas but they show significant differences for the turbulent kinetic energy field that controls the dispersion of pollutants.