@misc{PototskyArcherBestehornetal., author = {Pototsky, Andrey and Archer, Andrew J. and Bestehorn, Michael and Merkt, Domnic and Savelev, S. and Marchesoni, F.}, title = {Collective shuttling of attracting particles in asymmetric narrow channels}, language = {en} } @misc{PototskyOronBestehorn, author = {Pototsky, Andrey and Oron, Alexander and Bestehorn, Michael}, title = {Equilibrium shapes and floatability of static and vertically vibrated heavy liquid drops on the surface of a lighter fluid}, series = {Journal of Fluid Mechanics}, volume = {922}, journal = {Journal of Fluid Mechanics}, issn = {1469-7645}, doi = {10.1017/jfm.2021.546}, pages = {A31-1 -- A31-21}, abstract = {A small drop of a heavier fluid may float on the surface of a lighter fluid supported by surface tension forces. In equilibrium, the drop assumes a radially symmetric shape with a circular triple-phase contact line. We show that such a floating liquid drop with a sufficiently small volume has two distinct equilibrium shapes at terrestrial gravity: one with a larger and one with a smaller radius of the triple-phase contact line. Static stability analysis reveals that both shapes could be stable if the drop volume is below a certain critical value. Experiments conducted with μL-sized water drops floating on commercial oil support the existence of multiple contact line radii for a drop with fixed volume. Next, we experimentally study the floatability of a less viscous water drop on the surface of a more viscous and less dense oil, subjected to a low-frequency (Hz-order) vertical vibration. We find that in a certain range of amplitudes, vibration helps heavy liquid drops to stay afloat. The physical mechanism of the increased floatability is explained by the horizontal elongation of the drop driven by subharmonic Faraday waves. The average length of the triple-phase contact line increases as the drop elongates that leads to a larger average lifting force produced by the surface tension.}, language = {en} } @misc{BestehornPototsky, author = {Bestehorn, Michael and Pototsky, Andrey}, title = {Faraday instability and nonlinear pattern formation of a two-layer system: A reduced model}, series = {Physical Review Fluids}, volume = {1}, journal = {Physical Review Fluids}, number = {6}, issn = {2469-990X}, doi = {10.1103/PhysRevFluids.1.063905}, pages = {063905-1 -- 063905-24}, abstract = {Stability and pattern formation of a two-layer liquid system with large aspect ratio subjected to vertical harmonic oscillations is studied by means of an integrated boundary layer model. The lower layer rests on an oscillating solid substrate, the upper layer is separated by a deformable interface from the lower layer and bounded at the top with a second, free interface to the ambient passive air. The model is derived from the Navier-Stokes equations in long-wave approximation, including inertial terms. Applying a Floquet analysis, linear stability charts and dispersion relations are computed and compared with results from the full linearized Navier-Stokes equations and the long-wave approximation. Nonlinear Faraday patterns simultaneously occurring at the interface and at the film surface are studied by numerically solving the integrated boundary layer model in two and three spatial dimensions. For gravitationally stable two-layer films with a lighter fluid on top of the heavier fluid, we find squares, hexagons, quasiperiodic patterns with eightfold symmetry as well as localized states in the form of large scale depletion regions or finite depth holes, occurring at the interface and surface. For a Rayleigh-Taylor unstable combination (heavier fluid above the light one) we show that external vibration increases the lifetime of the film by delaying or completely suppressing the film rupture.}, language = {en} } @misc{PototskyBestehorn, author = {Pototsky, Andrey and Bestehorn, Michael}, title = {Faraday instability of a two-layer liquid film with a free upper surface}, series = {Physical Review Fluids}, volume = {1}, journal = {Physical Review Fluids}, number = {2}, issn = {2469-990X}, doi = {10.1103/PhysRevFluids.1.023901}, pages = {023901-1 -- 023901-18}, abstract = {We study the linear stability of a laterally extended flat two-layer liquid film under the influence of external vertical vibration. The first liquid layer rests on a vibrating solid plate and is overlaid by a second layer of immiscible fluid with deformable upper surface. Surface waves, excited as the result of the Faraday instability, can be characterized by a time-dependent relative amplitude of the displacements of the liquid-liquid and the liquid-gas interfaces. The in-phase displacements are associated with a zigzag (barotropic) mode and the antiphase displacement corresponds to the varicose thinning mode. We numerically determine the stability threshold in the vibrated two-layer film and compute the dispersion relation together with the decay rates of the surface waves in the absence of vibration. The in-phase and the antiphase displacements are strongly coupled in the vibrated system. The interplay between the Faraday and the Rayleigh-Taylor instabilities in the system with heavier fluid on top of a lighter fluid is analyzed.}, language = {en} } @misc{PototskyOronBestehorn, author = {Pototsky, Andrey and Oron, Alexander and Bestehorn, Michael}, title = {Vibration-induced floatation of a heavy liquid drop on a lighter liquid film}, series = {Physic of Fluids}, volume = {31}, journal = {Physic of Fluids}, number = {8}, issn = {1089-7666}, doi = {10.1063/1.5099661}, pages = {087101-1 -- 087101-13}, abstract = {We carry out a theoretical study of vibration-induced saturation of the Rayleigh-Taylor instability for an isolated liquid drop on the surface of a less dense finite-thickness carrier film. Without vibration, a heavy drop falls through the carrier film by forming a stretching liquid column until the bottom tip of the column reaches the solid substrate and the carrier film ruptures. We show that an externally applied vertical vibration prevents the rupture of the film and enables stable flotation of the drop. A hydrodynamic model is used to study the effect of inertia on the long-time dynamics of the drop. It is shown that rupture can only be prevented when the Reynolds number is nonzero.}, language = {en} } @misc{PototskyBestehorn, author = {Pototsky, Andrey and Bestehorn, Michael}, title = {Shaping liquid drops by vibration}, series = {epl : a letters journal exploring the frontiers of physics}, volume = {121}, journal = {epl : a letters journal exploring the frontiers of physics}, number = {4}, issn = {1286-4854}, doi = {10.1209/0295-5075/121/46001}, pages = {46001-p1 -- 46001-p6}, abstract = {We present and analyze a minimal hydrodynamic model of a vertically vibrated liquid drop that undergoes dynamic shape transformations. In agreement with experiments, a circular lens-shaped drop is unstable above a critical vibration amplitude, spontaneously elongating in the horizontal direction. Smaller drops elongate into localized states that oscillate with half of the vibration frequency. Larger drops evolve by transforming into a snake-like structure with gradually increasing length. The worm state is long-lasting with a potential to fragment into smaller drops.}, language = {en} } @article{BestehornPototskyThiele, author = {Bestehorn, Michael and Pototsky, Andrey and Thiele, Uwe}, title = {3D Large scale Marangoni convection in liquid films}, language = {en} } @article{MerktPototskyBestehornetal., author = {Merkt, Domnic and Pototsky, Andrey and Bestehorn, Michael and Thiele, Uwe}, title = {Long-wave theory of bounded two-layer films with a free liquid-liquid interface: Short and long-time evolution}, doi = {10.1063/1.1935487}, language = {en} } @article{PototskyBestehornMerktetal., author = {Pototsky, Andrey and Bestehorn, Michael and Merkt, Domnic and Thiele, Uwe}, title = {Alternative pathways of dewetting for a thin two-layer film of soft matter}, doi = {10.48550/arXiv.nlin/0401042}, language = {en} } @article{PototskyBestehornMerktetal., author = {Pototsky, Andrey and Bestehorn, Michael and Merkt, Domnic and Thiele, Uwe}, title = {Evolution of interface patterns of three-dimensional two-layer liquid films}, series = {Europhysics Letters}, volume = {74}, journal = {Europhysics Letters}, number = {4}, issn = {0302-072X}, doi = {10.1209/epl/i2006-10026-8}, pages = {665 -- 671}, language = {en} } @article{PototskyBestehornThiele, author = {Pototsky, Andrey and Bestehorn, Michael and Thiele, Uwe}, title = {Control of the structuring of thin softmatter films by means of different types of external disturbance}, language = {en} } @phdthesis{Pototsky, author = {Pototsky, Andrey}, title = {Pattern Formation in Thin One- and Two-layer Liquid Films}, publisher = {Brandenburgische Techn. Univ.}, address = {Cottbus}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-000000822}, language = {en} }