Computational fluid dynamics research

Computational fluid dynamics research in the Atmospheric Dispersion Modelling group is focusing 1) on the atmospheric boundary layer dynamics in local scale, and 2) in particular on the surface layer of the urban atmospheric boundary layers.

Computational fluid dynamics utilizes very high-resolution large-eddy simulation (LES) which is employed and further developed for these research areas. The LES model called PALM developed at Leibniz Universität Hannover is run on the Cray XC-30 supercomputer of FMI.

Dispersion of a gaseous emission in city surroundings.

The first research area includes especially studies of the dynamics of convective boundary layers in collaboration with Prof. Sergej Zilitinkevich. Various hypotheses are practically impossible to be tested based on measurements. Such hypotheses are tested using the LES modelling. This research aims at improved parameterizations and their calibration for numerical weather-prediction models and climate models, and better understanding of the underlying dynamics.

The second research area has several motivations. Detailed, building resolving LES modelling of urban canopy-layer flow and dispersion opens possibilities e.g. to more detailed and more reliable air-quality analyses, contingency planning and post analyses of hazardous material release accidents. Moreover, it can be applied to city-planning purposes to achieve better air-quality, pedestrian wind comfort and thus improved life quality as well as better energy efficiency in new urban areas being currently built or planned especially in Helsinki-region because of its increasing population.

Wind velocity distribution in atmospheric boundary layer.

Contact information

Senior scientist
Antti Hellsten
tel. +358 29 539 5566

fax +358 29 539 5403