In filtration processes it is necessary to consider the interaction of the fluid with the solid parts and the effect of particles carried in the fluid and accumulated on the solid. Traditionally, for investigation of the driving parameters, such as particle deposition and material influence, destructive tests are used. In order to provide accurate repeatable ambient requirements, simulations offer an attractive alternative. While other related publications deal with the large particle deposition model [2-5], this thesis focussed on the development of a solver to model fibre deformation effects. Pressure and traction forces, induced by fluid motion consequently lead to deformations of the solid part. According to this multi-physical problem, it is necessary to couple the differential equations of fluid motion, namely the Navier-Stokes equations and structural mechanical equations, Hooke’s law, for the solid region. For their numerical discretisation only one single computational mesh is used. This grid is changing with time and hence is recalculated at each time step to adjust to the deformation in order to conserve geometric consistency. The derived algorithm was summarized by one single solver and realised with the help of the Open Source, C++ based, computational fluid dynamics tool box OpenFOAM®. It was thoroughly validated by plausibility checks and available experimental data. With this, a strong tool for studying fluid-structure interaction phenomena on microscopic scale was developed. It was successfully applied on realistic, from CT-scans reconstructed fiber materials. Further on it was combined with the Lagrangian particle model. This provides the possibility of simultaneous simulation of all relevant physical phenomena by one single finite volume solver based on OpenFOAM®. Experiments showed a non linear behaviour of pressure drop in dependency of flow rates for soft filter materials. With the help of the newly developed filtration solver it was possible to prove this observation. Further on the particle deposition behaviour for different filter materials was investigated. New insights were gained, which underlined the high influence of the deformation of filter material on the overall filtration process. The final aim of the project is to design a filtration tool for the development and optimization of new high performance filter materials without need for performing time consuming and expensive experimental work.