Research

Waves, wakes and swimming

We study and model the forces on swimmers at the water surface to produce new rapid solver for controlling the navigation and stability of swimming robots.

Postural control of swimming snakes on water surface

As part of this project, I am seeking to understand the surface stabilisation mechanisms of semi-aquatic snakes (garter snakes, water moccasins) in order to develop bio-inspired robots capable of stabilising themselves at the surface. This ANR-funded project involves the following stages

Hydrostatic and hydrodynamic models coupled with non-linear geometric models (Cosserat model)
A robotic platform including a novel type of actuation (a controlled rolling movement) to stabilise the robots on the surface
Cross-over experiments between biology (thanks to our colleague G. Lemaux from the Nantes museum), physics and robotics.

Motor control by central patter generators and sensory feedback

In this area of research, I am working on theoretical models that account for the recovery of motor function in swimmers via sensory feedback.

Our study focuses on swimming robots (EPFL, team of AUke Ijspeert) whose servomotors are driven by a network of oscillators whose activity is modulated by exteroceptive (pressure) and proprioceptive (joint coordinates) sensory feedback.

Turbulent mixing and interfacial waves

I studied the mechanisms of turbulent mixing between two layers of fluids of different density, composed of water (upper stratum) and salt water (lower stratum), via interface waves. This stable configuration is disturbed by a turbulent jet that impinges perpendicularly on the interface, exciting coherent interface waves. The breaking of these waves causes mixing between the light and heavy fluids. The aim is to understand the physics of mixing and the couplings between turbulence and a stratified interface, and to compare the results with simulations of industrial codes for nuclear safety.

erosion_dynamics.avi

2D Turbulence

Two-dimensional flows have properties that differ greatly from the usual three-dimensional turbulence. They are characterised by the emergence of large-scale coherent vortex structures interacting with the highly turbulent flow. During my thesis, I studied a 2D turbulent flow numerically and experimentally. I experimentally characterised the emergence of these large-scale structures through the different flow regimes: laminar, chaotic, turbulent and condensed.

Precessing flows

Precessional flows are of vital importance in astrophysics (planets, accretion discs) and also in industrial applications (rocket tanks, rotating machines). They appear when a rotating flow is subjected to a second rotation, even a very small one. This flow is like enclosing a fluid in a spinning top whose axis of rotation rotates around a second axis. As part of my post-doctorate in Germany ([2014-2015]), I studied the dynamics of the waves generated by precession and the spatial and temporal properties of turbulent flow.

Google Sites

Report abuse