The main methodological contributions of the group concern Computational Fluid Dynamics (CFD) of unsteady vortical and/or turbulent flows at high Reynolds numbers. In particular, the development and validation of high performance methods and their implementation in HPC contexts are achieved: Eulerian methods (spectral, high order finite differences) and hybrid Eulerian-Lagrangian methods (vortex particle-mesh methods (VPM)). They also perform the development and validation of advanced subgrid-scale models including multi-scale models (regularized variational multiscale models (RVMS)) for high fidelity large-eddy simulation (LES) of turbulent flows, including multi-scale models, and also models with proper near-wall behavior (for wall-resolved LES and for wall-modeled LES).The areas of deployment of these tools cover both fundamental and applied problems in fluid mechanics. They thus cover central issues in fluid mechanics, stability, vortex dynamics, and turbulence but also complex flows such as aircraft wakes, wind turbine aerodynamics and wakes, and CROR systems for propulsion.
Other areas of deployment involve bio-propulsion problems and flow control. The group has also been strongly involved with the Cenaero: for helping in its creation and development, and also for research collaborations. In particular, this now concerns the assessment of the discontinuous Galerkin (DG) method for the simulation (DNS and LES) of complex turbulent flows in aerodynamics.
Particle methods, vortex methods and their high performance implementations
The groups of Philippe Chatelain and Grégoire Winckelmans work jointly on the development of high performance vortex methods for the simulation of high Reynolds number turbulent flows.
Ongoing methodological efforts include the development of techniques for the enforcement of solid boundary conditions. Among those, the work focuses on the development of both efficient penalization-based techniques and high-order immersed interface techniques.
Spatial adaptivity techniques are also studied in the context of Particle-Mesh methods. In those methods, the adaptivity is controlled by the Mesh representation of the fields but it needs to account for the advection of particles between regions of different resolutions. Multi-resolution and adaptive mesh refinement for particle methods are subjects of ongoing work.
A last area of research in vortex methods concerns their coupling to velocity-pressure solvers. The resulting approach then exploits the qualities of both methods: the Eulerian can adopt stretched meshes for the near-wall region and the Vortex method can efficiently advect the shed vortical structures away from the wall.
This research activities are led by Profs. G. Winckelmans and P. Chatelain.
