# Berlin 2012 – wissenschaftliches Programm

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# DY: Fachverband Dynamik und Statistische Physik

## DY 22: Posters I

### DY 22.18: Poster

### Mittwoch, 28. März 2012, 17:00–19:00, Poster A

**Biofilm growth in shear flows** — •Jörn Hartung and Björn Hof — Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen

The formation of biofilms in water distribution systems and medical equipment has detrimental effects (e.g. decrease in efficiency of water conduits and emergence of health risks). Pathogenic microorganisms capable of biofilm formation can spoil potable water and easily lead to infections in humans. Furthermore, biofouling in water distribution pipes decreases the cross section available for the bulk flow and increases the surface roughness which in turn leads to higher friction losses.

We investigate the influence of the Reynolds number on biofilm formation for laminar flow in the regime 500<Re<5000. While generally biofilms grow faster at low Reynolds numbers where the shear stresses are small, we surprisingly find a maximum growth for 1000<Re<2000. An explanation for this behaviour could be that the transport rate of nutrients is limited at small Reynolds numbers leading to lesser amounts of attached biofilm material. At increasing Reynolds numbers shear forces become more pronounced and facilitate detachment. At high Reynolds number we find in addition that the biofilms disturb the initially laminar flow and trigger turbulence which leads to a large drag increase.