Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 25: Fluid dynamics I

DY 25.3: Talk

Thursday, February 28, 2008, 12:00–12:15, MA 001

Complexity in small aspect ratio Taylor-Couette flow — •Ole Staack, Matti Heise, Jan Abshagen, and Gerd Pfister — Institute of Experimental and Applied Physics, Kiel, Germany

Taylor-Couette flow, i.e. a viscous fluid in the gap between two concentric rotating cylinders, is one of the classical hydrodynamic systems for investigating bifurcation events and nonlinear dynamics. For small aspect ratios the multiplicity of steady solutions is small. However, complex dynamical behavior, that appears abruptly from time dependent flow, can be observed at higher Reynolds numbers. Our present study is focused on the origin of this complexity. Therefore the underlying bifurcation structure has been investigated in an extended parameter space, unfolded by the rotation of the rigid end plates.

A rich diversity of time dependent modes and mode coupling has been observed. One example is a rotating wave with an azimuthal wave number m=2 rotating either in the same or the opposite azimuthal direction to the rotating inner cylinder. This direction reversion scenario includes frequency locking between the rotating wave and the stationary as well as the slowly rotating ’imperfect’ end plates.