Stability of a ferrofluid layer on a liquid substrate

Abstract

The stability of a horizontal magnetic fluid layer located on a liquid substrate in the alternating magnetic field orthogonal to the surface is experimentally investigated. Kerosene-based magnetite liquid stabilized with oleic acid (ferrofluid) and perfluorooctane (to create a liquid substrate) were chosen as working fluids. The presence of a free surface and interface in the magnetic fluid layer determines the influence of spatial characteristics of the system, such as the diameter of the cell and the thickness of the liquid layer, on the resonant frequency. The stability of the ferrofluid layer in an orthogonal stationary magnetic field is investigated, and the dependence of the critical field strength on the layer thickness is obtained. The dependences of intensity amplitude on the alternating magnetic field frequency are depicted for the ferrofluid layers of various initial thicknesses. The obtained stability curves show that the low frequency field (1–4 Hz) destabilizes the system, while the high frequency one (from 4 Hz and above) has a stabilizing effect.

The Disintegration of Magnetic Fluid Layer on Liquid and Solid Substrates in Vertical Magnetic Field

“…По сравнению со случаем твердой подложки [6] разрыв слоя магнитной жидкости на жидкой подложке происходил при значительно меньших значениях критической напряженности Hf* [24], т. к. для этого достаточно, чтобы суммарная амплитуда возмущений обеих поверхностей слоя превысила его толщину (рис. 3).…”