179 results found
Dallaston MC, Fontelos MA, Tseluiko D, et al., 2018, Discrete self-similarity in interfacial hydrodynamics and the formation of iterated structures, Phys. Rev. Lett., Vol: 120
The formation of iterated structures, such as satellite and sub-satellitedrops, filaments and bubbles, is a common feature in interfacial hydrodynamics.Here we undertake a computational and theoretical study of their origin in thecase of thin films of viscous fluids that are destabilized by long-rangemolecular or other forces. We demonstrate that iterated structures appear as aconsequence of discrete self-similarity, where certain patterns repeatthemselves, subject to rescaling, periodically in a logarithmic time scale. Theresult is an infinite sequence of ridges and filaments with similarityproperties. The character of these discretely self-similar solutions as theresult of a Hopf bifurcation from ordinarily self-similar solutions is alsodescribed.
Denner F, Charogiannis A, Pradas M, et al., 2018, Solitary waves on falling liquid films in the inertia-dominated regime, JOURNAL OF FLUID MECHANICS, Vol: 837, Pages: 491-519, ISSN: 0022-1120
Lin T-S, Tseluiko D, Blyth MG, et al., 2018, Continuation methods for time-periodic travelling-wave solutions to evolution equations, APPLIED MATHEMATICS LETTERS, Vol: 86, Pages: 291-297, ISSN: 0893-9659
Nold A, González MacDowell L, Sibley DN, et al., 2018, The vicinity of an equilibrium three-phase contact line using density-functional theory: density profiles normal to the fluid interface, Molecular Physics, Pages: 1-5, ISSN: 0026-8976
The paper by Nold et al. [Phys. Fluids 26 (7), 072001 (2014)] examined density profiles and the micro-scale structure of an equilibrium three-phase (liquid–vapour–solid) contact line in the immediate vicinity of the wall using elements from the statistical mechanics of classical fluids, namely density-functional theory. The present research note, building on the above work, further contributes to our understanding of the nanoscale structure of a contact line by quantifying the strong dependence of the liquid–vapour density profile on the normal distance to the interface, when compared to the dependence on the vertical distance to the substrate. A recent study by Benet et al. [J. Phys. Chem. C 118 (38), 22079 (2014)] has shown that this could explain the emergence of a film-height-dependent surface tension close to the wall, with implications for the Frumkin–Derjaguin theory.
Ravipati S, Aymard B, Kalliadasis S, et al., 2018, On the equilibrium contact angle of sessile liquid drops from molecular dynamics simulations, JOURNAL OF CHEMICAL PHYSICS, Vol: 148, ISSN: 0021-9606
Yatsyshin P, Duran-Olivencia MA, Kalliadasis S, 2018, Microscopic aspects of wetting using classical density-functional theory., Journal of Physics: Condensed Matter, Vol: 30, ISSN: 0953-8984
Wetting is a rather efficient mechanism for nucleation of a phase (typically liquid) on the interface between two other phases (typically solid and gas). In many experimentally accessible cases of wetting, the interplay between the substrate structure, and the fluid-fluid and fluid-substrate intermolecular interactions brings about an entire ``zoo" of possible fluid configurations, such as liquid films with a thickness of a few nanometers, liquid nanodrops and liquid bridges. These fluid configurations are often associated with phase transitions occurring at the solid-gas interface and at lengths of just several molecular diameters away from the substrate. In this special issue article, we demonstrate how a fully microscopic classical density-functional framework can be applied to the efficient, rational and systematic exploration of the rich phase space of wetting phenomena. We consider a number of model prototype systems such as wetting on a planar wall, a chemically patterned wall and a wedge. Through density-functional computations we demonstrate that for these simply structured substrates the behaviour of the solid-gas interface is already highly complex and non-trivial.
Yatsyshin P, Kalliadasis S, 2018, Classical density-functional theory studies of fluid adsorption on nanopatterned planar surfaces, Pages: 171-185, ISSN: 2194-1009
© Springer International Publishing AG, part of Springer Nature 2018. This contribution is based on our talk at the BIRS Workshop on “Coupled Mathematical Models for Physical and Biological Nanoscale Systems and Their Applications”. Our aim here is to summarize and bring together recent advances in wetting of nanostructured surfaces, using classical density-functional theory (DFT). Classical DFT is an ab initio theoretical-computational framework with a firm foundation in statistical physics allowing us to systematically account for the fluid spatial inhomogeneity, as well as for the non-localities of intermolecular fluid-fluid and fluid-substrate interactions. The cornerstone of classical DFT, is to express the grand free energy of the system as a functional of its one-body density, thus generating a hierarchy of N-body correlation functions. Unconstrained minimization of a properly approximated free-energy functional with respect to the one-body density then yields the basic DFT equation. And since most macroscopic quantities of interest can often be cast as averages over a one-body distribution, this equation provides a very useful and accessible computational tool. Indeed, there has been a rapid growth of classical DFT applications across a broad variety of fields, including phase transitions in solutions of macromolecules, interfacial phenomena, and even nucleation. Here we attempt to give a taste of what simple equilibrium DFT models look like, and what they can and cannot capture, as far as wetting on chemically heterogeneous substrates is concerned. We review recent progress in the understanding of planar prewetting and interface unbending on such substrates and compute substrate-fluid interfaces and wetting isotherms.
Yatsyshin P, Parry AO, Rascon C, et al., 2018, Wetting of a plane with a narrow solvophobic stripe, MOLECULAR PHYSICS, Vol: 116, Pages: 1990-1997, ISSN: 0026-8976
Consider the dynamics of a healing film driven by surface tension, that is, the inward spreading process of a liquid film to fill a hole. The film is modelled using the lubrication (or thin-film) approximation, which results in a fourth-order nonlinear partial differential equation. We obtain a self-similar solution describing the early-time relaxation of an initial step-function condition and a family of self-similar solutions governing the finite-time healing. The similarity exponent of this family of solutionsis not determined purely from scaling arguments; instead, the scaling exponent is a function of the finite thickness of the prewetting film, which we determine numerically. Thus, the solutions that govern the finite-time healing are self-similar solutions of the second kind. Laboratory experiments and time-dependent computations of the partialdifferential equation are also performed. We compare the self-similar profiles and exponents, obtained by matching the estimated prewetting film thickness, with both measurements in experiments and time-dependent computations near the healing time, and we observe good agreement in each case.
Charogiannis, Denner, van Wachem, et al., 2017, Detailed Hydrodynamic Characterization of Harmonically Excited Falling-Film Flows: A Combined Experimental and Computational Study, Physical Review Fluids, Vol: 2, Pages: 014002-014002, ISSN: 2469-990X
We present results from the simultaneous application of planar laser-induced uorescence (PLIF)and particle image/tracking velocimetry, complemented by direct numerical simulations, aimed atthe detailed hydrodynamic characterization of harmonically excited liquid- lm ows falling underthe action of gravity. The experimental campaign comprises four di erent aqueous-glycerol solutionscorresponding to four Kapitza numbers (Ka= 14, 85, 350, 1800), spanning the Reynolds numberrangeRe= 2:3
Charogiannis A, Denner F, van Wachem BGM, et al., 2017, Statistical characteristics of falling-film flows: A synergistic approach at the crossroads of direct numerical simulations and experiments, PHYSICAL REVIEW FLUIDS, Vol: 2, ISSN: 2469-990X
Dallaston MC, Tseluiko D, Zheng Z, et al., 2017, Self-similar finite-time singularity formation in degenerate parabolic equations arising in thin-film flows, NONLINEARITY, Vol: 30, Pages: 2647-2666, ISSN: 0951-7715
Duran-Olivencia MA, Yatsyshin P, Goddard BD, et al., 2017, General framework for fluctuating dynamic density functional theory, NEW JOURNAL OF PHYSICS, Vol: 19, ISSN: 1367-2630
Gomes SN, Kalliadasis S, Papageorgiou DT, et al., 2017, Controlling roughening processes in the stochastic Kuramoto-Sivashinsky equation, PHYSICA D-NONLINEAR PHENOMENA, Vol: 348, Pages: 33-43, ISSN: 0167-2789
Gotoda H, Pradas M, Kalliadasis S, 2017, Chaotic versus stochastic behavior in active-dissipative nonlinear systems, PHYSICAL REVIEW FLUIDS, Vol: 2, ISSN: 2469-990X
Morciano M, Fasano M, Nold A, et al., 2017, Nonequilibrium molecular dynamics simulations of nanoconfined fluids at solid-liquid interfaces, JOURNAL OF CHEMICAL PHYSICS, Vol: 146, ISSN: 0021-9606
Nold A, Goddard BD, Yatsyshin P, et al., 2017, Pseudospectral methods for density functional theory in bounded and unbounded domains, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 334, Pages: 639-664, ISSN: 0021-9991
Schmuck M, Kalliadasis S, 2017, RATE OF CONVERGENCE OF GENERAL PHASE FIELD EQUATIONS IN STRONGLY HETEROGENEOUS MEDIA TOWARD THEIR HOMOGENIZED LIMIT, SIAM JOURNAL ON APPLIED MATHEMATICS, Vol: 77, Pages: 1471-1492, ISSN: 0036-1399
Yatsyshin P, Parry AO, Rascon C, et al., 2017, Classical density functional study of wetting transitions on nanopatterned surfaces, JOURNAL OF PHYSICS-CONDENSED MATTER, Vol: 29, ISSN: 0953-8984
Charogiannis A, Pradas M, Denner F, et al., 2016, Hydrodynamic characteristics of harmonically excited thin-film flows: Experiments and computations, 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
Dallaston MC, Tseluiko D, Kalliadasis S, 2016, Dynamics of a thin film flowing down a heated wall with finite thermal diffusivity, PHYSICAL REVIEW FLUIDS, Vol: 1, ISSN: 2469-990X
Denner F, Pradas M, Charogiannis A, et al., 2016, Self-similarity of solitary waves on inertia-dominated falling liquid films, PHYSICAL REVIEW E, Vol: 93, ISSN: 2470-0045
Duncan AB, Kalliadasis S, Pavliotis GA, et al., 2016, Noise-induced transitions in rugged energy landscapes, PHYSICAL REVIEW E, Vol: 94, ISSN: 2470-0045
Duran-Olivencia MA, Goddard BD, Kalliadasis S, 2016, Dynamical Density Functional Theory for Orientable Colloids Including Inertia and Hydrodynamic Interactions, JOURNAL OF STATISTICAL PHYSICS, Vol: 164, Pages: 785-809, ISSN: 0022-4715
Goddard BD, Nold A, Kalliadasis S, 2016, Dynamical density functional theory with hydrodynamic interactions in confined geometries, JOURNAL OF CHEMICAL PHYSICS, Vol: 145, ISSN: 0021-9606
Pradas M, Savva N, Benziger JB, et al., 2016, Dynamics of Fattening and Thinning 2D Sessile Droplets, LANGMUIR, Vol: 32, Pages: 4736-4745, ISSN: 0743-7463
Schmuck M, Kalliadasis S, 2016, General framework for adsorption processes on dynamic interfaces, JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, Vol: 49, ISSN: 1751-8113
Yatsyshin P, Kalliadasis S, 2016, Mean-field phenomenology of wetting in nanogrooves, MOLECULAR PHYSICS, Vol: 114, Pages: 2688-2699, ISSN: 0026-8976
Yatsyshin P, Parry AO, Kalliadasis S, 2016, Complete prewetting, JOURNAL OF PHYSICS-CONDENSED MATTER, Vol: 28, ISSN: 0953-8984
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