Eur. Phys. J. Special Topics 219, 89-98 (2013)
https://doi.org/10.1140/epjst/e2013-01784-4

Regular Article

Instability of Marangoni flow in the presence of an insoluble surfactant. Experiments

¹ Institute of Continuous Media Mechanics, Acad. Koroleva 1, Perm 614013, Russia
² 1.Physikalisches Institut der Justus-Liebig-Universitaet, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
³ Seconda Universita di Napoli, Dipartimento di Ingegneria Aerospaziale Meccanica, via Roma 29, 81031 Aversa, Italy

^a e-mail: alex_mizev@icmm.ru

Received: 1 July 2012
Revised: 18 January 2013
Published online: 19 March 2013

Abstract

The stability and structure of solutocapillary Marangoni flow initiated by a localized concentration source in the presence of an adsorbed layer of insoluble surfactant is investigated experimentally. It has been established that the main axisymmetric flow becomes unstable with respect to azimuthally periodic disturbances which leads to the appearance of the surface flow with a multi-vortex structure. The structure of the secondary flow is investigated depending on the intensity of the main flow and on the surface density of the surfactant. It has been shown that the azimuthal wave number increases with the growth of the Marangoni number and decreases with the surface density of the surfactant. A threshold value of the surface density of the surfactant, at which the Marangoni flow does not occur, has been defined.