Coupling of OpenFOAM with a Lagrangian vortex particle method for external aerodynamic simulations

In the field of computational aerodynamics, it is vital to develop tools that can accurately, but also efficiently, simulate the flow around bluff objects and calculate the aerodynamic forces acting on them. When strong body–vortex interactions take place, the simulations become more demanding, since complex phenomena appear. To address this issue, hybrid Eulerian–Lagrangian solvers have been developed and are increasingly used in the field. In this paper, a Vortex Particle Method (VPM) is coupled with the OpenFOAM software. The Eulerian solver (OpenFOAM) resolves the regions close to the solid boundaries, while the vortex particles evolve the wake downstream, significantly reducing artificial diffusion. The coupling strategy and the validation results of a hybrid code based on the domain decomposition technique are presented. This work is the first to couple OpenFOAM with a Lagrangian solver in the framework of a hybrid solver. Our objective is twofold: to verify the capability of OpenFOAM to run with a VPM and to validate the hybrid solver using benchmark cases. We demonstrate the validation of the solver on the Lamb–Oseen vortex case, the dipole case in the unbounded domain, and the flow around a cylinder at Re = 550. Our results show that coupling OpenFOAM with a VPM can be achieved without complications and efficiently reproduces the results of pure Eulerian simulations.