Hybrid Eulerian-Lagrangian Method for Complex 3D Viscous Flows

The Vortex Particle Method (VPM) is used to represent incompressible and viscous flow fields with the help of small particles of vorticity. This method is especially convenient for simulating the transport and decay of vortex structures in the wake as well as flow mixing but behaves poorly when interacting with solid boundaries. Unsteady Reynolds-Averaged Navier-Stokes (URANS) are amongst the high-fidelity methods particularly well adapted for accurate prediction of turbulent boundary-layer. However, URANS simulations are prone to numerical dissipation and can become computationally expensive for the accurate prediction of complex configurations involving multiple flow interactions for large time and space scales. This study aims to provide a multi-fidelity aerodynamic method based on the hybridization of the Lagrangian VPM for the far field flow and the Eulerian URANS solver for the near-wall flow. The Hybrid method is first validated on the flow around a sphere to observe its capacity to properly generate and transfer vortex structures between the Eulerian and Lagrangian Domains. The simulation of a high Reynolds configuration is eventually shown using the case of a wing in an unbounded flow, which provides with an accurate flow solution with reduced computational cost compared to classical fully Eulerian methods.