Flow simulations are becoming increasingly complex and require dedicated solution strategies to solve large and complex scenarios. Example applications are found in hemodynamics, nuclear reactor simulations and, wind modeling. It can be beneficial to divide such complex flow domains into smaller subdomains, which can be simulated by solvers that best resolve the flow characteristics of the respective region. However, these subdomains need to be coupled. The coupling library preCICE allows to couple various popular fluid solvers with a black-box coupling approach. This thesis serves as validation for the fluid-fluid module of the preCICE OpenFOAM adapter. Before coupling multiple fluid solvers with varying features, we should assess the possibilities and limitations of coupling two similar fluid solvers. We investigate incompressible laminar flow partitioned in two domains. The investigation is done using the OpenFOAM solvers icoFoam and pimpleFoam, with a Dirichlet-Neumann surface coupling via preCICE. Fully developed flow can be coupled perfectly using mass-flux aware boundary conditions. In that case, the maximum relative error for velocity compared to the monolithic solution is in the order of 1e-5. Coupling of a developing flow profile on a coarse mesh results in maximum errors in the order of 1e-2 at the cells next to the interface. The error depends linearly on the magnitude of the velocity gradient and the cell size. In cells further away from the interface, the error is approximately one order smaller. Higher order of accuracy around the coupling interface can be reached by manipulating OpenFOAM solvers and thereby abandoning the non-invasive plugin approach of the adapter and the idea of preCICE to treat solvers as black boxes. Having established a baseline for the error that we can expect in fluid-fluid coupling, we extend the fluid-fluid module of the OpenFOAM adapter to support more complex flows and cover a wider range of OpenFOAM solvers. We add temperature to the coupled variables using a Dirichlet-Neumann coupling approach. The relative error for temperature obtained in the validation case using buoyantPimpleFoam is in the order of 1e-6. A further addition to the fluid-fluid module is custom inlet-outlet boundary conditions, which allow backflow across the coupling interface. They incorporate the flux-aware behavior that we established for uni-directional flow coupling and they can be set on both sides of the interface, regardless of the flow direction. Overall, this thesis provides an understanding for the capabilities and limitations of coupling laminar flows with the fluid-fluid module of the preCICE OpenFOAM adapter and paves the path towards coupling more complex fluid flows in the future.      «

Flow simulations are becoming increasingly complex and require dedicated solution strategies to solve large and complex scenarios. Example applications are found in hemodynamics, nuclear reactor simulations and, wind modeling. It can be beneficial to divide such complex flow domains into smaller subdomains, which can be simulated by solvers that best resolve the flow characteristics of the respective region. However, these subdomains need to be coupled. The coupling library preCICE allows to co...     »