My main research themes are :
- Flow control of separated flows
- Hydrodynamic instabilities
- Transition to turbulence in shear flows
- Automotive aerodynamics
Open-loop and closed-loop control of separated flows using visual sensors (with N. Gautier)
Closed-loop control of the separated flow downstream a Backward-Facing Step (BFS) using a pulsed slotted-jet as the actuator and real-time PIV measurement as input :
Recirculation bubble downstream a BFS: natural uncontrolled flow (grey area) together with the controlled flow (black area).
Time serie showing the instantaneous velocity field donwstream the BFS for the uncontrolled and controlled flow:
Acoustic manipulation of particles or living cells in microchannels
Acoustophoresis of particles (with M. Hoyos and former Ph. D. student O. Dron)
Principle of the acoustic focusing of particles in suspension in a micro-cavity or a micro-channel.
Movie showing the focusing of the particles at mid-height of the channel: focusing_crop (converti)
We also demonstrated that it is possible to move the sheet of particles along the height of the channel by varying the acoustic frequency:
It opens the way to many new applications under investigation.
Instabilities of a Jet-In-Crossflow (JICF) in collaboration with T. Cambonie
Transition to turbulence in shear flows
Subcritical transition to turbulence in a Plane Poiseuille Flow (PPF), with G. Lemoult and J. E. Wesfreid
Visualization of a the structure of a turbulent spot growing in the subcritical régime :
Visualisation of the nucleation of a turbulent spot growing in the PPF after an initial pulse in the middle of the channel :
Self-Sustained Process (SSP) in boundary layer with T. Duriez and J. E. Wesfreid.
We have shown experimentally that the SSP is indeed a key mechanism in the transition to turbulence of wall-bounded shear flows. It was achieved using small cylinders to force the transition of a subcritical boundary layer :
Creation of streaks of high and low streamwise velocity downstream the cylinders.