Research
Deformable particles in turbulence
Currently I am working on flexible fibers in turbulent flows. The deformations of a fiber are negligible when the fiber length is smaller than a critical length. This characteristic scale depends on the mechanical properties of the fiber, the fluid properties (density and viscosity) and the power injected in the turbulence. My studies are mainly focused on two questions: how are deformed the fibers and how do these deformations influence the transport of a fiber in turbulence.
I am also interested in the collective dynamics of fibers in turbulent and laminar flow. This investigation was initiated by the observation of aegagropila on mediterranean beaches. Of course, this process occurs in many industrial application like in the paper industry and in everyday life observations (dust and hair aggregates, ...).
Turbulence near the critical point of a fluid
At the critical point several physical properties of the fluid diverge
as the compressibility, the viscosity, the relaxation time scale... Some divergences
may be very useful for fluid mechanics as it allows to reach new regime.
For example, in a small rotor-stator setup, we have generated
turbulent flow with Reynolds number around 107 and Mach number
around 0.5. These characteristics are very close to the Reynolds and Mach
number reach in the aerospace industry.
From a fundamental point of view, the interaction between the divergence of
the physical properties and the flow rise some new question. For example
what is the modification of the turbulence by the divergence of the density
fluctuation which can be of the same order of the Kolmogorov length?
What is the modification of the flow dynamics due to the relaxation time
scale divergence close to the critical point?
Magnetohydrodynamics
My work wass focused on the dynamo instability and the transition from hydrodynamics turbulence to magnetohydrodynamics turbulence.