Previous talks at the SCCS Colloquium

Markus Mühlhäußer: Partitioned flow simulations with preCICE and OpenFOAM

SCCS Colloquium |

Flow simulations are becoming increasingly large and complex. It can be beneficial to divide such complex flow domains into smaller, coupled subdomains, which are simulated by individual, dedicated solvers. The multiphysics library preCICE allows to couple various popular fluid solvers with a black-box coupling approach.
This thesis serves as an in-depth investigation and validation for the fluid-fluid module of the preCICE OpenFOAM adapter. Incompressible, laminar flow is partitioned and solved by coupling OpenFOAM solvers using a Dirichlet-Neumann surface coupling approach. The results are compared to monolithic OpenFOAM simulations. Fully developed flow can be coupled almost perfectly using mass-flux aware boundary conditions. Coupling developing flow profiles leads to an error at the interface that depends linearly on the magnitude of the velocity gradient and the discretization size. Higher accuracy around the coupling interface can only be reached by manipulating OpenFOAM solvers and thereby violating the idea of preCICE to treat solvers as black boxes.
Additionally, the fluid-fluid module is extended to couple temperature with great accuracy for one validation case. Lastly, custom inlet-outlet boundary conditions are implemented for pressure and velocity. These allow backflow across the interface and can be set on both sides of the interface, regardless of the flow direction. These additional features pave the path towards coupling more complex flow scenarios including turbulence and buoyancy.

Master's thesis presentation. Markus is advised by Gerasimos Chourdakis.