The working group at LH2 has recently got a major focus on the coupling of different model concepts. The necessity to couple models arises due to different reasons and one can distinguish between coupling concepts in time (sequential coupling, de-coupled solution of equations for weakly interacting processes, etc.) and in space (different model concepts in different compartments of the model domain).
The fields of application are very broad and include, for example, fuel-cells. The performance of a fuel-cell is crucially dependent on the oxygen supply at the reaction layer. In a PEM fuel-cell, the oxygen is provided by a free gas flow through the channels of the gas distributor and has to pass the porous diffusion layer to reach the reaction layer. Therefore, it is necessary to adequately describe the flow in the different compartments, in this case the porous medium (e.g. Darcy flow) and the gas distributor (free flow, e.g. approximated as 1D pipe flow).
Similar interaction between different types of flow fields requiring specifically adapted mathematic equations occur, for example, in biological tissues where flow through blood vessels follows different equations than flow in interstitial or connective tissues. Applications of coupled flow models in human tissue is of great interest, for example, for the development of new improved cancer treatment.