CFD modelling of flow and pollutant dispersion in urban areas, taking into account the radiative effects of the buildings
Event details
| Date | 25.05.2009 |
| Hour | 16:15 |
| Speaker | Dr Maya Milliez, EDF R&D, France |
| Location |
GR B30
|
| Category | Conferences - Seminars |
Understanding the phenomena occurring in urban areas, such as flow motion and pollutant dispersion, has a double aim: the first one is to evaluate the impact on population and the environment on a local scale the second is to describe the bulk effects of buildings on flow and concentration fields. In the present work, detailed numerical simulations are performed on an idealized urban area, modelled as regular rows of large rectangular obstacles. The simulations are performed at full scale with the three-dimensional Computational Fluid Dynamics model Mercure_Saturne (developed by EDF R&D and CEREA), which is adapted to atmospheric flow and pollution dispersion. In this work, we use a RANS approach with a k-eps turbulence closure. The simulations are evaluated with the near full-scale experiment MUST (Mock Urban Setting Test), which was conducted for the Defense Threat Reduction Agency in Utah's West Desert at US Army's Dugway Proving Ground. It consists of releases of inert gas in a field of 10 x 12 shipping containers and provides numerous measurements. The dynamical effects have been extensively studied using CFD techniques, usually assuming a neutral atmosphere and neglecting the thermal effects. Nevertheless, radiative transfer plays an important role because of its influence on the urban canopy energy budget. In order to take into account the radiation budget in simulations of pollution dispersion in urban areas, we have developed a radiative scheme adapted to complex geometry, by adapting to atmospheric radiative transfers a radiative heat transfer scheme. This radiative scheme is based on the Discrete Ordinate Method to solve the radiative transfer equation in a semi-transparent media. The new model was validated with idealized cases for the solar and infrared schemes and the results were compared to thermal measurements available in some of the cases of the MUST experiment.The current developments of this work are to study in detail the coupling between the dynamics and the radiative transfers and to model explicitly a part of a real urban area. This modelling will be applied to the city of Toulouse and the results will be compared to the measurements from the CAPITOUL campaign.
Practical information
- General public
- Free
Contact
- A. Berne