Berlin 2018 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 42: Turbulence

DY 42.2: Talk

Wednesday, March 14, 2018, 10:15–10:30, BH-N 128

Scalable exact coherent structures for the turbulent cascade — •Stefan Zammert and Bruno Eckhardt — Philipps-Universität Marburg, Marburg, Germany

Exact solutions of the Navier-Stokes equations play a key role in the formation of subcritical turbulence. The appearance of three-dimensional turbulence was shown to be connected to secondary bifurcations of such structures in various flows. However, an explanation of the evolution of the observed spatial complexity, e.g. the multiple scales of turbulence, is still missing.

We will show different families of exact coherent states of plane Couette flow which can be scaled in their spatial extends to obtain a hierarchy of exact coherent states (Eckhardt & Zammert: Nonlinearity, to appear). While one of these families is localized in the center of the channel and independent of the walls, another one is attached to the walls and reminiscent of so-called attached eddies. The structures propose a potential entry to explain the turbulent cascade using exact coherent structures and thus by methods from dynamical systems theory.