Gravitational and magnetic convection in magnetic colloids

Experiments were performed to examine the influence of homogeneous magnetic field on convection instability and flows in a layer of magnetic fluid heated from one wide side and cooled from another. The temperature sensors were used for measurement of heat transport across the layer. Visualization of flow patterns was provided by a liquid crystal sheet. The results indicate that with the help of a magnetic field it is possible to control the convection stability, intensity of the heat transfer and the form of convection motions. The interaction of gravitational and magnetic convection mechanisms for different orientations of the layer and magnetic field were studied. The essential influence of gravitational sedimentation of magnetic particles and their aggregates on convection in magnetic colloids is shown. A number of non-linear regimes of convection, including localized states and repeated long-wave transients from convection to conduction were observed.