The main objective of this thesis is to derive a mathematical model of a ferrofluid seal which can be used for an accurate and robust numerical simulation. The mathematical model considers the effect of redistribution of magnetic particles in a moving ferrofluid, which stays in presence of a strong outer magnetic field. The presence of fluid-gas surfaces implies the free surface problem to be taken into consideration. Numerical tests determine the parameter range at which the mathematical model is applicable and answer the main question, how the effects of fluid motion and particle concentration interact.weiterlesen