Depinning of two-dimensional liquid ridges and three-dimensional drops on an inclined substrate is studied within the lubrication approximation. The structures are pinned to wetting heterogeneities arising from variations strength short-range contribution disjoining pressure. case a periodic array hydrophobic stripes transverse slope in detail using combination direct numerical simulation branch-following techniques. Under appropriate conditions may either depin slide downslope as increased,...

Strong electric fields produce forces that can overcome the surface tension in thin liquid polymer films and this way induce an instability of free film, triggers formation structures on a micrometer length scale. Here, we study experimentally polymer–air–polymer system for several combinations films. These results are accompanied by theoretical considerations based coupled long-wave time evolution equations two profiles. The linear stability nonlinear investigated compared to experimental...

Lubrication equations allow to describe many structurin processes of thin liquid films. We develop and apply numerical tools suitable for their analysis employing a dynamical systems approach. In particular, we present time integration algorithm based on exponential propagation an steady-state continuation. both algorithms Cayley transform is employed overcome problems resulting from scale separation in space time. An adaptive time-step allows study the dynamics close hetero- or homoclinic...

In the ideal crack model in eddy-current testing frame, field-flaw is equivalent to a current dipole layer on its surface. This has shown efficiency, as well for computing accuracy, CPU time. The goal of this paper improve taking into account inclination, conductance, and low thickness crack.

Abstract. Time-dependent dynamical simulations related to convective motion in a spherical gap under central force field due the dielectrophoretic effect are discussed. This work is part of preparation GEOFLOW-experiment which planned run microgravity environment. The goal this experiment simulation large-scale geophysical or astrophysical framework. problem new because of, on one hand, nature (dielectrophoretic effect) and, another high degree symmetries system, e.g. top-bottom reflection....

This study is motivated by the issue of pumping particle through a periodic modulated channel. We focus on simplified deterministic model small inertia particles within Stokes flow framework that we call ``ratchet flow.'' A path-following method employed in parameter space order to retrace scenario which from bounded solutions leads transport. Depending whether magnitude drag moderate or large, two main transport mechanisms are identified role parity symmetry differs. For large drag, induced...

The numerical investigation of convective flows in the radial force field caused by an oscillating electric between spherical surfaces has been performed. A temperature difference (T_{1}>T_{2}) as well a triggers fluid flow similar to Rayleigh-Bénard convection. onset studied means linear stability analysis function radius ratio η=R_{1}/R_{2}. influence temperature-dependent viscosity investigated detail. We found that varying contrast β=ν(T_{2})/ν(T_{1}) β=1 (constant viscosity) and β=50...

Spherical Rayleigh-Bénard convection under the influence of an artificial central force field produced by so-called dielectrophoretic effect is studied as a simplified model flow in outer earth core. The fluid motion there most probably driving earth's dynamo and energy source for magnetic field. Studying convective flows earth-like geometry could lead to deeper understanding basics these processes.

Abstract A macroscopic model of water infiltration is developed and applied to a stratified porous medium containing hydrophilic hydrophobic layers. The governing equation gradient dynamics as in the Richards but which wettability term replaces suction pressure, taking into account effective action matter. resulting fourth-order PDE similar lubrication or Cahn-Hilliard equations known reproduce complex such intermittency fingering instability. makes it possible simulate finite spreading...

This study investigates the flow of a thin annular film driven by an axial force in micro-tube. Partial wetting is taken into account using diffuse interface theory and dynamics approximated long-wave mesoscopic model. One goals to understand transition between partial complete when driving increases. Two scenarios, depending on curvature, lead wetting. For low arises ridge spreading, whereas for sufficiently large it via coating sliding ridge. The latter regime has no equivalent plane...

This work focuses on the simulation and experimental study of directional wicking water a surface structured by open microchannels. Stainless steel was chosen as material for structure motivated industrial applications fuel cells. Inspired nature literature, we designed fin type structure. Using Selective Laser Melting (SLM) manufactured additively with resolution down to about 30 μm. The geometry three different scalings both experiments show that efficiency transport depends dimensionless...

Abstract The problem of convection in a self‐gravitating spherical shell fluid is commonly encountered sciences like astrophysics and geophysics (earth's liquid core). GEOFLOW‐experiment project the European Space Agency order to perform Rayleigh‐Bénard on International Station micro‐gravity environment: central force field simulated by dielectrophoretic one. Beyond critical Rayleigh number Ra c , generically an unique ℓ mode becomes unstable only stationary or travelling waves solutions are...

For thin cracks, in eddy current testing (ECT), the field‐flaw interaction is equivalent to a dipole layer on its surface. The density solution of an integral equation with hyperstrong kernel. variation coil impedance and distribution directly obtained from this by surface integration. There numerical difficulty evaluate accurately integrals for near crack. In fact, due singular kernel dyadic Green function, integration quasi‐singular. A specific regularisation algorithm developed overcome...

Objective of GeoFlow experiment is to study thermally-driven rotating fluids, in order investigate the stability, pattern formation, and transition turbulence viscous incompressible fluids contained between concentric, co-axially spheres. These physical mechanisms are important for a large number astrophysical geophysical problems showing flows spherical geometry driven by rotation convection: example, explain mantle convection Earth, or flow planet’s interior. The European microgravity...