François Feuillebois

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We present an experimental approach to flow profiling within femtoliter sample volumes, which allows the high-precision measurements at the solid interface. The method is based on the spatial cross-correlation of the fluorescence response from labeled tracer particles (latex nanospheres or single dye molecules). Two excitation volumes, separated by a few(More)
Superhydrophobic surfaces reduce drag by combining hydrophobicity and roughness to trap gas bubbles in a microscopic texture. Recent work has focused on specific cases, such as arrays of pillars or grooves, with limited theoretical guidance. Here, we consider the experimentally relevant limit of thin channels and obtain rigorous bounds on the effective slip(More)
Lubrication expressions for the friction coefficients of a spherical particle moving in a fluid between and along two parallel solid walls are explicitly evaluated in the low-Reynolds-number regime. They are used to determine lubrication expression for the particle free motion under an ambient Poiseuille flow. The range of validity and the accuracy of the(More)
We analyze the rotational and translational motion of two close spheres in a fluid at low Reynolds number to investigate if their surfaces come into mechanical contact. The rotational motion of a sphere settling close to another fixed ball is calculated from a model in which contact interactions between the spheres are added to the gravitational and(More)
We report the results of direct measurements of velocity profiles in a microchannel with hydrophobic and hydrophilic walls, using a new high-precision method of double-focus spatial fluorescence cross correlation under a confocal microscope. In the vicinity of both walls the measured velocity profiles do not go to zero by supplying a plateau of constant(More)
François Feuillebois1,†, Maria L. Ekiel-Jeżewska2, Eligiusz Wajnryb2, Antoine Sellier3 and Jerzy Bławzdziewicz4 1LIMSI-CNRS, UPR 3251, Rue John von Neumann Campus Universitaire d’Orsay Bât 508, 91405 Orsay CEDEX, France 2Institute of Fundamental Technological Research, Polish Academy of Sciences, Pawińskiego 5b, 02-106 Warsaw, Poland 3LadHyX, École(More)
The one-phase Stefan problem in enthalpy formulation, describing the freezing of initially supercooled droplets that impact on solid surfaces, is solved numerically by the finite volume method on a nonorthogonal body fitted coordinate system, numerically generated. The general case of third order boundary conditions on the droplet is considered. The(More)
We model the solidification and subsequent cooling of a supercooled liquid droplet that is lying on a cold solid substrate after impact. It is assumed that solidification occurs for a given fixed droplet shape. The shapes used by the model are a sphere, truncated spheres, and an experimentally registered droplet shape. The freezing process is(More)
We provide some general theoretical results to guide the optimization of transverse hydrodynamic phenomena in superhydrophobic channels. Our focus is on the canonical micro- and nanofluidic geometry of a parallel-plate channel with an arbitrary two-component (low-slip and high-slip) coarse texture, varying on scales larger than the channel thickness. By(More)