On Magnetic Field Control Experiments of Ferrofluid Convection Motion

Abstract

Summary The experiments have been performed on the stability of buoyancy-driven flows of a ferrofluid for the cases of an inclined and vertical orientation of thin cylindrical encloser. Visualization of flow patterns is provided by a temperature-sensitive liquid crystal sheet which serves as the lower surface of a transparent heat exchanger. The local temperature sensor is used for measurement of heat transport across the fluid layer. The results indicate that with the help of an external homogeneous transversal magnetic field it is possible to control the stability of thermogravitational shear flow under vertical orientation of the layer, i.e. induce the thermomagnetic mode of instability with vertical orientation of longitudinal convection rolls. As numerous experimental investigations show the origin of concentration density gradients due to gravity sedimentation of magnetic particles and their aggregates results in traveling wave regimes of Rayleigh and thermomagnetic convection flows.