research activities in the FILMS team at IEMN
current research subjects are focused on the understanding of the
out-of-equilibrium dynamics of flows where surface tension forces
play a dominant role. This happens when one of the typical scale of
the problem is between 1 micron and a few mm. Current applications
are mostly related to the handling of small droplets, that are more
and more utilized in discrete microfluidics. Typical situations are
the displacement of sessile droplets against capillary retention
forces acting at the contact-line. With surface acoustic waves
(SAW), it is possible to induce both the inner mixing and
displacement of the drop.
reminiscent issue, is to understand what governs the forced
imbibition in textured non-wetting (superhydrophobic) surfaces.
We use both drop-impact and electrowetting to induce
impalement within such surfaces.
generally, the interaction of a sessile drop with its substrate, and
particularly the case of dynamical wetting, still offers hot
debates (see these two recent reviews on the subject here
side-projects, I have investigated the famous 'Edgerton's crown'
problem, ie the fingering pattern following the impact of a drop on a
thin fluid layer. I have also been studying the instabilities
(surface deformations) and rupture of a liquid curtain subjected to
impact and electrowetting on textured super-hydrophobic surfaces.
Farzam Zoueshtiagh, Alain Merlen (team FILMS - IEMN)
Florian Lapierre, Vincent Thomy (team BIOMEMS - IEMN)
Nhung Phuong Nguyen, Yannick Coffinier, Rabah Boukheroub & Ralf
Blossey (Institut de Recherche Interdisciplinaire – IRI)
displacement by ultrasonic surface acoustic waves (SAW).
Farzam Zoueshtiagh, Michael Baudoin, Olivier Bou Matar & Alain
Merlen (team FILMS – IEMN)
of levitating drops.
and unstable front propagation of supercooled liquids in confined
Michael Baudoin (team FILMS - IEMN)
in a liquid curtain subject to local perturbations.
and formation of structures during the splashing of drops.
taken at between 0.8 and 1.5 ms after impact. A drop of silicon oil
targeting a thin layer of fluid at V between 3 m/s and 3.5 m/s. An
annular sheet develops after impact, surrounded by a liquid 'rim'.
The destabilization of the rim (initially smooth and unperturbed)
shows a fingering pattern with a well-defined
higher Reynolds number
(experiments carried out with water), a noisy structure of tiny jets
appears at the early stage and the subsequent wavelength of the
fingering structure is less regular.
t ≈ 0.15
t ≈ 2
t ≈ 4 ms
motions on sessile drops induced by vibrations of the substrate.
Snapshots (t=0, 4.76,
9.05 and 13.33 ms) of a 5 ml
of glycerin on an inclined plate (inclination 45
degrees) shaken at 60 Hz.
are movies to download:
: a 2100 fr/sec. movie showing the rocking motion of a climbing drop,
when shaken at 60 Hz.
: a 20 fr/sec. movie, showing a climbing drop. Snapshots are taken
every 3 periods, at the same phase, then enabling to see the global
: a 2100 fr/sec movie of an horizontal plate shaken diagonally (an
analogue of the previous situation, but suppressing gravity), showing
ultimately a pearling instability at the drop's trailing end.
: a 100 fr/sec movie, showing both the shaking and the deformation of
the drop. First, the drop slides down the incline, and once the
shaking is prescribed it climbs up!
of star-shaped drops in a Leidenfrost experiment and on vibrated
From n=2 to n=13: Various
spatial modes appearing when a drop is put on a shaken hydrophobic
substrate (frequency ranges from 15 to 200 Hz).
break of axisymmetry is observed with
Leidenfrost drops (Propanol, substrate temperature between 200 and
Previous research activities :
- PhD Thesis: STRUCTURES AND
NON-LINEAR DYNAMICS OF FALLING LIQUIDS (At PMMH
A gallery of pictures ...
(In french only).
- STATIC GRANULAR PACKINGS :
Mechanical response and the influence of the packing
preparation (At the former LMDH
laboratory , Paris, Newly settled here)
- CONTROL OF
THERMOCAPILLARY INSTABILITIES (At KTH
Mekanik, Stockholm, Sweden).
FORCED IMBIBITION AND DRAINAGE IN HYDROPHOBIC POROUS MEDIA (At KTH
Mekanik and Faxen
Laboratory, Stockholm, Sweden).