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.
RevealFlight Concerted Research Action: the reproduction of bird flying gaits and of self-organization into formations
The RevealFlight Concerted Research Action aims at shedding light on the efficiency optimization mechanisms deployed by biological flyers. We will focus on birds, and in particular on migratory birds, which are known to exhibit such efficiency-seeking mechanisms at several levels, while maintaining relatively stable flight conditions, leading to impressive results.
At the level of an individual flyer, biomechanical and aerodynamic factors have long been identified but their interconnection has never been studied in details. On the one hand, the morphology and the neuro-muscular configuration of the bird can be seen as the frame and actuation layer that realize the gait of the bird. On the other hand, this gait is also meant to exploit aerodynamic phenomena at various scales: a bird indeed achieves lift through the unsteady aerodynamics of its flapping wings but also through fine-scale flow control mechanisms by means of feathers and wing compliance. At the level of the flock, it is well known that migratory birds adopt flight formations in which downstream flock members exploit the upwash regions of upstream birds' wakes resulting in efficiency gains. But the mechanisms by which they self-organize to achieve these gains are not fully understood.
The over-arching objective of the RevealFlight project is to provide an improved comprehensive understanding of bird flocks flight by capturing the interplay between the physics, the bio-engineering disciplines, and the problematic of control and self-organization.
To that end, RevealFlight proposes to synthesize the flight mechanics of birds into a unified framework, combining biomechanical, sensory, aerodynamic and social interaction models, in order to reproduce the flying gaits and the interactions within a flock. This multi-disciplinary and fully coupled approach brings several advantages. It enforces consistency between the biomechanical stresses and the sustentation forces and enables the unified treatment of flight as a problem that encompasses all the physics ranging from muscle activation to flow turbulence.
More information, as well as job openings, are available on the RevealFlight website.