Selected results of a model validation exercise

The concentration fields calculated with three Gaussian models and one Lagrangian dispersion model are validated against a set of SF6 concentration data provided by the German environmental programme BWPLUS. The source was a pig fattening unit in fairly flat terrain. The results reveal that, in flat terrain with steady undisturbed flow, the use of Gauss models is still justified, whereas Lagrangian models should be used whenever the flow is modified by obstacles or topography.