Regensburg 2016 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 57: Focus Session: Turbulence - From Pattern Formation to Stochastic Disorder

DY 57.12: Talk

Thursday, March 10, 2016, 18:15–18:30, H46

Cluster analysis of coherent structures in Rayleigh-Bénard convection — •Oliver Kamps — Center for Nonlinear Science, University of Münster

Turbulence is an ubiquitous physical phenomenon settled somewhere between randomness and order. On the one hand turbulent flows seem to be irregular and chaotic but on the other hand one can observe coherent structures, patterns or superstructures constituting the flow. The identification of these structures and their dynamics is crucial for the understanding of turbulent flows and therefore for applications in science and engineering.

In many cases the coherent structures live only for a certain time span followed by a rapid transition to another state like a different coherent structure. Such a transition can be regarded as an extreme event which is accompanied by strong distortions of observables like heat transport or mixing. In our approach we use clustering based methods [1] in order to identify these non-stationary states, estimate dynamical models for their time evolution and to anticipate extreme events. As example we apply our methods to Rayleigh-Bénard convection showing reversals.
[1] A. Hutt, M. Svensén, F. Kruggel and R. Friedrich, Phys. Rev. E 61 (2000)