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DY: Fachverband Dynamik und Statistische Physik

DY 70: Poster: Flows, Patterns, Delay, Reaction Diffusion

DY 70.7: Poster

Donnerstag, 15. März 2018, 15:30–18:00, Poster A

Magnetic wave calming — •Alexandra Fischer, Armin Kögel, and Reinhard Richter — Experimentalphysik 5, Universität Bayreuth, Germany

One of the most prominent hydrodynamic instabilities in nature is the Kelvin-Helmholtz instability [1]: Wind blowing over water causes surface waves, if a critical velocity is surpassed. Here we demonstrate for the first time, that the magnetic susceptibility of a ferrofluid can be exploited in order to calm the waves by applying a magnetic field parallel to the surface. We measure the spatial growth rate, the critical velocity depending on the frequency of the interfacial wave, and the dispersion relation while varying the magnetic field strength. Finally we compare our values to the non viscous theory as put forward by Rosensweig [2].

1. Hermann v. Helmholtz, Über discontinuierliche Flüssigkeitsbewegungen. Berl. Ber. p. 215. (1868).
2. Ronald E. Rosensweig, Ferrohydrodynamics Cambridge University Press, Cambridge (1985).