Berlin 2008 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 25: Fluid dynamics I

DY 25.2: Vortrag

Donnerstag, 28. Februar 2008, 11:45–12:00, MA 001

Spiral vortices in perturbed circular Couette flow — •Jan Abshagen — Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany

Circular Couette flow is well-known for its centrifugal instability that results in the formation of either Taylor or spiral vortices depending on the rate of differential rotation of the two cylinders that confine the viscous fluid in radial direction. Due to the presence of axial end plates as often used in experimental systems the circular Couette profile is deformed. This results in a secondary circulation, the so-called Ekman vortices. The role of axial end plates for the onset of Taylor vortices in the 'classical' Taylor-Couette setup with non-rotating outer cylinder has been studied in depth and recently finite-length effects have been found at the onset of spiral vortices in counter-rotating Taylor-Couette flow. Here, the role of the secondary circulation for the appearance and the properties of spiral vortices in perturbed circular Couette flow is investigated. Focus is given to the case of co-rotating cylinders which has been considered so far as a prototype for the appearance of Taylor vortices due to centrifugal instability.