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DY: Dynamik und Statistische Physik

DY 38: Fluid Dynamics

DY 38.3: Vortrag

Mittwoch, 29. März 2006, 17:15–17:30, SCH 251

Propagating fronts in spiral Poiseuille flow — •Matti Heise, Jan Abshagen, and Gerd Pfister — Institute of Experimental and Applied Physics, University of Kiel, Germany

One of the classical hydrodynamic systems for the study of Hopf bifurcation with O(2)-symmetry is counter rotating Taylor Couette flow. This is the flow of a viscous liquid in the gap between two concentric rotating cylinders. We present the results of an experimental study on the transition between two different types of spiral vortices in counter rotating spiral Poiseuille flow, the Taylor Couette flow between two counter rotating cylinders in the presence of an axial through flow. As a result of an applied axial through flow the ’classical’ Hopf bifurcation to spiral vortices splits up and a primary and secondary branch of down- and upward propagating spirals, respectively, as well as a transient quasiperiodic flow appear. The bifurcation structure observed in this open flow experiment is in qualitative agreement with predictions from theory of Hopf bifurcation with broken reflection symmetry and also in quantitative agreement with results from recent numerical calculations. We also observed the transition from upward to downward propagating spirals in form of a progagating front in spiral Poiseuille flow.