Dresden 2011 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 13: Fluid Dynamics and Turbulence I

DY 13.7: Vortrag

Dienstag, 15. März 2011, 12:00–12:15, ZEU 118

Magnetic spatial forcing of a ferrofluid layer — •Thomas Friedrich, Ingo Rehberg, and Reinhard Richter — Experimentalphysik 5, Universität Bayreuth

Historically, spatial forcing of a pattern forming system was first studied experimentally in electroconvection [1]. More recently, inclined layer convection was measured under the influence of lamellar surface corrugations [2]. In both cases, stripes are the first convection pattern beyond a threshold.

The Rosensweig instability in a layer of ferrofluid can provide a primary instability to hexagons if a homogeneous magnetic field normal to the flat surface is applied [3,4]. In case of a tilted magnetic field, a primary instability to stripes can be observed [5]. As a consequence, switching between these two basic types is possible in one single system. We explore how both configurations respond to a stripe like modulation of the magnetic induction. To detect the fluid’s response to the different configurations of magnetic fields, x-ray imaging technique [6] is used.

[1]M. Lowe et al, Phys. Rev. Lett., 51(9):786–789, 1983

[2]G. Seiden et al, Phys. Rev. Lett., 101(21):214503, 2008.

[3]M. D. Cowley and R. E. Rosensweig, J. Fluid Mech.,30:671, 1967.

[4]R. Richter, Physik Journal, 7:39–44, 2008.

[5]B. Reimann et al, Phys. Rev. E, 71:055202(R), 2005.

[6]R. Richter, J. Bläsing, Rev. Sci. Instrum. 72:1729-1733 (2001)