Some features of the Marangoni rings growth in ferrofluids

V. Igropoulo - V. Samonov

Stavropol State University 355009 Stavropol, Russia }

Abstract
The dynamics of growth and deformation of Marangoni rings in ferrofluids at different relations between the surface tension forces and volume forces induced by an external magnetic field are surveyed; the mathematical model featuring the motion of fluid for this process is simulated and solved for special cases. Parameter Ri introduced in the previous papers by the authors is used to quantitatively analyze the relation between the surface tension forces and the magnetic forces and to define prospective applicability of the obtained solution. The extreme cases, when Ri  >>  1 and Ri  <<  1 are considered, and at Ri  ∼   1 some qualitative assumptions on the character of fluid motion are formulated. The opportunity to use the obtained results, when develop ``dynamic methods'' for measuring the surface tension of magnetic fluids and investigate a possible dependence of this value on the intensity of an external magnetic field, is shown. Figs 4, Refs 18.