Eur. Phys. J. E (2014) 37: 101
https://doi.org/10.1140/epje/i2014-14101-7

Regular Article

Inclined layer convection in a colloidal suspension with negative Soret coefficient at large solutal Rayleigh numbers

¹ Dipartimento di Fisica, Università degli Studi di Milano, I-20133, Milano, Italy
² Laboratoire des Fluides Complexes et leurs Réservoirs, Université de Pau et des Pays de l’Adour, 64600, Anglet, France
³ Department of Physics, University of Fribourg, CH-1700, Fribourg, Switzerland

^* e-mail: alberto.vailati@unimi.it

Received: 11 July 2014
Revised: 2 October 2014
Accepted: 8 October 2014
Published online: 29 October 2014

Abstract

Convection in an inclined layer of fluid is affected by the presence of a component of the acceleration of gravity perpendicular to the density gradient that drives the convective motion. In this work we investigate the solutal convection of a colloidal suspension characterized by a negative Soret coefficient. Convection is induced by heating the suspension from above, and at large solutal Rayleigh numbers (of the order of 10⁷-10⁸) convective spoke patterns form. We show that in the presence of a marginal inclination of the cell as small as 19mrad the isotropy of the spoke pattern is broken and the convective patterns tend to align in the direction of the inclination. At intermediate inclinations of the order of 33mrad ordered square patterns are obtained, while at inclination of the order of 67mrad the strong shear flow determined by the inclination gives rise to ascending and descending sheets of fluid aligned parallel to the direction of inclination.