Regensburg 2013 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 33: Poster II

DY 33.37: Poster

Thursday, March 14, 2013, 17:00–19:00, Poster C

Transitions in double-diffusive finger convection — •Matthias Kellner and Thomas Müller — Institut für Geophysik der Georg-August Universität, Göttingen, Deutschland

An electrodeposition cell is used to sustain a destabilizing concentration difference of copper ions in aqueous solution and a stabilizing temperature gradient between the top and bottom boundaries of the cell. The thermal Rayleigh number was varied for a set destabilizing chemical Rayleigh number. Finger convection is observed, although the overall density gradient is destabilizing (|λ| < 1). A transition from finger regime to Rayleigh-Benard convection is observed for a fixed ratios of the Rayleigh numbers. This is marked by a change from an anisotropic to an isotropic velocity field. The Sherwood number increases with decreasing Rayleigh number towards its maximum at the transition, after which it will drop again in the convective zone. Numerical simulations concerning this scenario are done.