The Rosensweig instability at the interface between ferrofluids and immiscible fluids

In this study, the Rosensweig instability at the interface between ferrofluids and other immiscible fluids is systematically studied. Stable water based ferrofluids with saturated magnetization as high as 25.4 kA/m are successfully synthesized. The surface tension, density and viscosity of water based ferrofluids used in this study are systematically and scientifically studied. Concentrated coils magnetic field generator is constructed to evaluate the experimental results of Rosensweig instability at the interface between ferrofluids and immiscible fluids. Combined with the theoretical results, the simulation results are obtained from our model to evaluate the Rosensweig instability at the interfaces. The well accordance between experimental results and the theoretical simulation results indicates that the Rosensweig instability is easily generating at interfaces between ferrofluids and oils than the interfaces between ferrofluids and air. This result could be attributed to the surface tension and buoyance of liquids on the ferrofluids.