Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Posters I

DY 22.27: Poster

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

Directed percolation model for turbulence transition in shear flows — •Korinna Allhoff¹ and Bruno Eckhardt² — ¹Institut für Festkörperphysik, TU Darmstadt — ²Fachbereich Physik, Philipps-Universität Marburg

We analyze a 1+1-dimensional directed percolation system as a model for the spatio-temporal aspects of the turbulence transition in pipe flow and other shear flows. Space and time are discrete, and the model is characterized by two parameters: one describes the probability to remain turbulent in the next step, the other characterizes the spreading of turbulence to the neighboring cells. The transition to a persistent turbulence is evident in mean field arguments, but the actual values are considerably renormalized by fluctuations. Extensive numerical tests show that the model falls into the universality class of one-dimensional directed percolation. We conclude with a discussion of the spreading of localized perturbations and an extension to two-dimensional systems.