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UP: Fachverband Umweltphysik

UP 5: Poster: Atmosphäre und Aerosole: Datenauswertung und Modellierung

UP 5.4: Poster

Tuesday, March 11, 2008, 16:30–19:00, Poster B1

Spreading of pollutants and tracer particles in 2 dimensional erratic flows — •Hans Lustfeld — IFF-1, Forschungszentrum Jülich, 52425 Jülich

We investigated the transient time regime of tracer particles (pollutants)in 2 dimensional flows selecting in particular those which demonstrate the existence of the so called turbulent diffusion. The spreading matrix determining the range of tracer particles emitted from a source was calculated for simple time independent flows. It was shown that the spreading can increase i) linearly with time, ii) with a third power and - what is remarkable - iii) exponentially fast [1].

Here we repeat the calculations for more realistic, 'erratic flows', i.e. flows with more or less randomly changing directions. We show that the same phenomena i) - iii) occur. In particular after a time t_c a crossover from linear to exponential increase of the spreading is still quite possible.

[1] H. Lustfeld, G. Bene, Z. Kaufmann and G. Szabó, preprint.