Lorentz Center - Physics of Micro- and Nanofluids from 9 Jun 2008 through 20 Jun 2008
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    Physics of Micro- and Nanofluids
    from 9 Jun 2008 through 20 Jun 2008

The properties of fluids dynamics in extremely small systems and in

The properties of fluids dynamics in extremely small systems and in
the proximity of interfaces has been raised from the very beginning of
hydrodynamics, but still occupy a very important place in contemporary
science and technology. One may cite many examples: impact problems,
e.g. liquid droplets on solid surfaces or bluff bodies on liquid
surfaces, with many applications from fertilizer spreading in
agriculture to motion of torpedoes for military purposes; drag
reducting effects by polymers and bubbles, whose origin is still much
debated; miniaturizing fluidic systems to develop lab-on-a-chip (and
where the enhancement of viscous damping at micrometric scales makes
it necessary to look for new solutions for fluid manipulation); fluid
dynamics in biological systems and the understanding of locomotion at
small Reynolds number; nanorheology, for example lubrication flows, or
flows in nanopores and around nanotubes.

Over the last decade, the development of new techniques, both at the
experimental and computational level, have allowed to gain much
insight into the dynamics at the different scale involved:
nanohydrodynamics, dynamical surface force apparatus and atomic force
microscopy, particle image velocimetry at the micron scale, high speed
video imaging, but also molecular dynamics simulations, continuum like
approaches (e.g. Lattice Boltzmann or phase field techniques) and the
recent efforts to develop multiscale approaches for the simulations of
flows, etc.  Many questions remain however open and the understanding
of the interplay of the dynamics at the different scales involved
remains to be investigated and understood.  At the lowest microscopic
level, surface properties result from the complex interplay of many
physical and chemical ingredients: roughness, affinity to the fluid or
vapor, surface charges (resulting from dissociation), surfactant
adsorption, etc.  At a more macroscopic scale, the influence of these
ingredients on the interface properties should be rationalized using
established surface concepts like wetting, hydrodynamics boundary
condition or surface (e.g. Marangoni) stresses.  Yet, from a dynamical
point of view, very little is known concerning the mutual influence of
these ingredients on the interface dynamics, nor its potential
consequence on the flow pattern at much larger, macroscopic scales.
We would like to acquire knowledge from the simplest but
representative systems, in order to be able to put this expertise in
the development of complex devices.

Some questions, particularly in the context of micro and nanoflows,
have already been posed, here we would like to better rationalize
them, in such a way to ease the approach to these problem.

At present there are several experimental challenges, which may
strongly impact on the field, and progresses in these directions will
be reported and discussed during the workshop.

We would like to bring together experimentalists, computer scientists,
and theoreticians to disentangle the many effects that are
intrinsically connected at the various scales.  The focus of the
workshop will be on the physical aspects related to the above
mentioned problematics.  One important point will be to gather
scientist with different domain of specialization in fluid dynamics,
biophysics, chemistry, and micro- and nano-fabrication, in order to
share their experience and give the opportunity to induce exchanges
between these different communities.