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Influence of parametric modulation on the onset of thermomagnetic convection
Author(s) -
Engler H.,
Odenbach S.
Publication year - 2009
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200910230
Subject(s) - thermomagnetic convection , ferrofluid , magnetic field , convection , mechanics , condensed matter physics , magnetic pressure , combined forced and natural convection , materials science , flow (mathematics) , physics , temperature gradient , natural convection , magnetization , meteorology , quantum mechanics
Magnetic fluids – so called ferrofluids – are suspensions of nano‐scaled particles in an appropriate carrier liquid. The flow properties of these fluids can be influenced by applying an external magnetic field. It is possible to introduce a magnetic force in a horizontal ferrofluid layer which is able to drive a convective flow. The magnetic force arises in the presence of an external magnetic field if a temperature gradient exists in the fluid gap. The behaviour of the onset of convection depends on the strength of the external magnetic field and on the temperature gradient. In this paper the onset of convection under the influence of time‐modulated magnetic field has been investigated. The experimental results presented here show a shift in the onset of convection depending on the frequency of the external magnetic field. This behaviour confirms in principle the theoretical predictions which are also presented here. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)