Regensburg 2004 – scientific programme

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.80: Poster

Thursday, March 11, 2004, 16:00–18:00, Poster D

A phenomenological model for ferrofluid droplet dynamics in a shear flow — •Nana Sadowsky, Patrick Ilg, and Siegfried Hess — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin

Hydrostatics and hydrodynamics of ferrofluid droplets give valuable information on magnetic and dynamical properties of the magnetizable fluid [1].

While the equilibrium deformation of the ferrofluid droplet as a function of the applied magnetic field is known experimentally [1], the non-equilibrium dynamics remain rather unknown so far. Here, we propose a phenomenological model for the dynamics of ferrofluid droplets in the presence of shear flow. Generalizing the approach of [2], ferrofluid droplets are modeled as deformable and orientable ellipsoids of revolution.

The combined effects of a magnetic field and a shear flow on the orientation and deformation of the droplets are studied. It is found that the hydrodynamic drag leads to a flow alignment of the droplet orientation. Predictions for the alignment angle as a function of the applied field are presented. Some comparisons to experimental data [3] in the absence of shear are made.

[1] E. Blums, A. Cebers, M.M. Maiorov, Magnetic Fluids, deGruyter, Berlin 1997.

[2] P. Ilg and M. Kröger, Phys. Rev. E 66, 021501-1 (2002)

[3] A. Lebedev, A. Engel, K.I. Morozov and H. Bauke, New Journal of Physics 5, 57.1-57.20 (2003)