Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: POSTERS Magnetic Soft Matter

CPP 12.10: Poster

Dienstag, 24. März 2009, 14:00–16:30, P3

Thermomagnetic convection influenced by a parametric modulated magnetic field — •Harald Engler and Stefan Odenbach — Lehrstuhl für Magnetofluiddynamik, Technische Universität Dresden, 01062 Dresden

Previous theoretical investigations on thermal convection have shown that the behaviour of the onset of convection where the characteristic of the heat flux changes from a conductive to a convective state depends on the frequency of the driving force. The implementation of an experimental setup to review the theoretical predictions fails due to the immense technical effort to provide a time-modulated driving force. A way out of these technical difficulties affords the fact that by applying an external magnetic field a magnetic force in ferrofluids arises which is able to drive a convective flow. The external magnetic field can thus be arranged to provide a time-dependent progress of the field strength leading to a time-modulated magnetic force. This kind of convection which is driven by the magnetic force is called thermomagnetic convection. The experiments have shown a shift in the onset of convection that means for certain ranges of the frequencies of the magnetic force the convection is stabilized or destabilized. The results of the experimental investigations as well as the experimental setup to indicate the onset of convection will be presented at the talk.