POF: Interfacial Flows http://scitation.aip.org/ POF: Interfacial Flows Observation of collision and oscillation of microdroplets with extremely large shear deformation http://link.aip.org/link/?PHF/24/022103/1&agg=rss Tatsuya Yamada and Keiji Sakai<br/> We measured the viscosity and surface tension of various liquids under large (~10 s) shear deformation. Oscillation of a 10-[mu]m size microdroplet is brought about by the head-on collision of two droplets. Since the Reynolds number is as small as 100, the motion of the liquid is stable and the dyna ... [Phys. Fluids 24, 022103 (2012)] published Wed Feb 8, 2012. Thermocapillary motion of a slender viscous droplet in a channel http://link.aip.org/link/?PHF/24/022102/1&agg=rss E. Katz, M. Haj, A. M. Leshansky, and A. Nepomnyashchy<br/> We extend the previously developed low-capillary-number asymptotic theory of thermocapillary motion of a long bubble and a moderately viscous droplet in a channel [S. K. Wilson, The effect of an axial temperature gradient on the steady motion of a large droplet in a tube, J. Eng. Math. 29, 205 (1995 ... [Phys. Fluids 24, 022102 (2012)] published Tue Feb 7, 2012. Bouncing, coalescence, and separation in head-on collision of unequal-size droplets http://link.aip.org/link/?PHF/24/022101/1&agg=rss Chenglong Tang, Peng Zhang, and Chung K. Law<br/> The dynamics of head-on collision of unequal-size droplets were experimentally and theoretically investigated, with emphasis on identifying distinct collision outcomes and interpreting the size-ratio dependence. A unified regime diagram in terms of bouncing, permanent coalescence, and separation aft ... [Phys. Fluids 24, 022101 (2012)] published Wed Feb 1, 2012. Stability and breakup of confined threads http://link.aip.org/link/?PHF/24/012102/1&agg=rss P. J. A. Janssen, H. E. H. Meijer, and P. D. Anderson<br/> A boundary-integral method for periodic arrays of drops, threads or sheets between parallel walls is presented. The Green's functions take the form of a far-field Hele-Shaw description, which is used to generate periodic Green's functions for the parallel-wall configuration. The method is applied to ... [Phys. Fluids 24, 012102 (2012)] published Tue Jan 31, 2012. Transient reduction of the drag coefficient of charged droplets via the convective reversal of stagnant caps http://link.aip.org/link/?PHF/24/012101/1&agg=rss Brad S. Hamlin and William D. Ristenpart<br/> Droplets are frequently observed to move as if they were solid rather than liquid, i.e., with no slip at the liquid-liquid interface. This behavior is usually explained in terms of the so-called stagnant cap model, in which surfactants accumulate at the trailing edge of the droplet, immobilizing the ... [Phys. Fluids 24, 012101 (2012)] published Mon Jan 23, 2012. Wicking flow through microchannels http://link.aip.org/link/?PHF/23/122108/1&agg=rss Hadi Mehrabian, Peng Gao, and James J. Feng<br/> We report numerical simulations of wicking through micropores of two types of geometries, axisymmetric tubes with contractions and expansions of the cross section, and two-dimensional planar channels with a Y-shaped bifurcation. The aim is to gain a detailed understanding of the interfacial dynamics ... [Phys. Fluids 23, 122108 (2011)] published Tue Dec 27, 2011. Scaling percolation in thin porous layers http://link.aip.org/link/?PHF/23/122107/1&agg=rss E. F. Medici and J. S. Allen<br/> Percolation in porous media is a complex process that depends on the flow rate, material, and fluids properties as well as the boundary conditions. Traditional methods of characterizing percolation rely upon visual observation of a flow pattern or a pressure-saturation relation valid only in the lim ... [Phys. Fluids 23, 122107 (2011)] published Fri Dec 23, 2011. Surfactant-driven dynamics of liquid lenses http://link.aip.org/link/?PHF/23/122106/1&agg=rss George Karapetsas, Richard V. Craster, and Omar K. Matar<br/> Sessile liquid lenses spreading over a fluid layer, in the presence of Marangoni stresses due to surfactants, show a surprisingly wide range of interesting behaviour ranging from complete spreading of the lens, to spreading followed by retraction, to sustained pulsating oscillations. Models for the ... [Phys. Fluids 23, 122106 (2011)] published Thu Dec 22, 2011. Formation of organized nanostructures from unstable bilayers of thin metallic liquids http://link.aip.org/link/?PHF/23/122105/1&agg=rss Mikhail Khenner, Sagar Yadavali, and Ramki Kalyanaraman<br/> Dewetting of pulsed-laser irradiated, thin (<20 nm), optically reflective metallic bilayers on an optically transparent substrate with a reflective support layer is studied within the lubrication equations model. A steady-state bilayer film thickness (h) dependent temperature profile is derived base ... [Phys. Fluids 23, 122105 (2011)] published Tue Dec 20, 2011. Sustained inertial-capillary oscillations and jet formation in displacement flow in a tube http://link.aip.org/link/?PHF/23/122104/1&agg=rss Yi Sui and Peter D. M. Spelt<br/> We study inertial effects in the displacement of a fluid in a capillary by a more viscous fluid, using a numerical method. A level-set approach is employed to track the meniscus, and a Navier slip boundary condition is imposed in order to alleviate a stress singularity at the moving contact line. Va ... [Phys. Fluids 23, 122104 (2011)] published Fri Dec 16, 2011. On the validity of a universal solution for viscous capillary jets http://link.aip.org/link/?PHF/23/122103/1&agg=rss J. M. Montanero, M. A. Herrada, C. Ferrera, E. J. Vega, and A. M. Ganan-Calvo<br/> In this paper, we assess the validity of a universal solution based on the slenderness approximation to describe the velocity and shape of viscous capillary jets produced by two very different mechanisms: the action of the constant gravity force and the focusing effect of a coflowing gas stream. In ... [Phys. Fluids 23, 122103 (2011)] published Fri Dec 16, 2011. Gravity-driven flow over heated, porous, wavy surfaces http://link.aip.org/link/?PHF/23/122102/1&agg=rss K. A. Ogden, S. J. D. D'Alessio, and J. P. Pascal<br/> The method of weighted residuals for thin film flow down an inclined plane is extended to include the effects of bottom waviness, heating, and permeability in this study. A bottom slip condition is used to account for permeability and a constant temperature bottom boundary condition is applied. A we ... [Phys. Fluids 23, 122102 (2011)] published Fri Dec 16, 2011. Asymptotic behavior of a retracting two-dimensional fluid sheet http://link.aip.org/link/?PHF/23/122101/1&agg=rss Leonardo Gordillo, Gilou Agbaglah, Laurent Duchemin, and Christophe Josserand<br/> Two-dimensional (2D) capillary retraction of a viscous liquid film is studied using numerical and analytical approaches for both diphasic and free surface flows. Full 2D Navier-Stokes equations are integrated numerically for the diphasic case, while one-dimensional (1D) free surface model equations ... [Phys. Fluids 23, 122101 (2011)] published Wed Dec 7, 2011. Molecular dynamics study of the processes in the vicinity of the n-dodecane vapour/liquid interface http://link.aip.org/link/?PHF/23/112104/1&agg=rss Jian-Fei Xie, Sergei S. Sazhin, and Bing-Yang Cao<br/> Molecular dynamics (MD) simulation is used to study the evaporation and condensation of n-dodecane (CH), the closest approximation to Diesel fuel. The interactions in chain-like molecular structures are modelled using an optimised potential for liquid simulation (OPLS). The thickness of the transiti ... [Phys. Fluids 23, 112104 (2011)] published Tue Nov 29, 2011. Maximum speed of dewetting on a fiber http://link.aip.org/link/?PHF/23/112103/1&agg=rss Tak Shing Chan, Thomas Gueudre, and Jacco H. Snoeijer<br/> A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. We theoretically investigate this forced wetting transition for axisymmetric menisci on fibers of varying radii. First, we use a matched asymptotic expansion and derive the maximum speed ... [Phys. Fluids 23, 112103 (2011)] published Fri Nov 11, 2011. Optical interference effect on pattern formation in thin liquid films on solid substrates induced by irradiative heating http://link.aip.org/link/?PHF/23/112102/1&agg=rss Fumihiro Saeki, Shigehisa Fukui, and Hiroshige Matsuoka<br/> The pattern formation in thin liquid films on solid substrates induced by irradiative heating is investigated. A model to describe the evolution of both the film surface profile and temperature field in the system is developed, in which the energy absorption into the film and substrate, and the ener ... [Phys. Fluids 23, 112102 (2011)] published Wed Nov 9, 2011. Shock-wave solutions in two-layer channel flow. II. Linear and nonlinear stability http://link.aip.org/link/?PHF/23/112101/1&agg=rss A. Mavromoustaki, O. K. Matar, and R. V. Craster<br/> We investigate the flow of two immiscible fluids in an inclined channel, building on the work presented in Part I of this study. In this paper, we examine the stability of the flow to spanwise perturbations in both the linear and nonlinear regimes. The evolution equation governing the interfacial dy ... [Phys. Fluids 23, 112101 (2011)] published Tue Nov 1, 2011. The effect of air leakage and heat exchange on the decay of entrapped air pocket slamming oscillations http://link.aip.org/link/?PHF/23/102107/1&agg=rss Bjorn C. Abrahamsen and Odd M. Faltinsen<br/> The phenomenon studied in this work is that of an air pocket entrapped by a free surface water wave inside a rectangular tank at a high filling level. The wave, which is a gravity wave, is caused by forced horizontal motion which is constructed in a particular way, in order to entrap an air pocket a ... [Phys. Fluids 23, 102107 (2011)] published Fri Oct 21, 2011. Features of the rupture of free hanging liquid film under the action of a thermal load http://link.aip.org/link/?PHF/23/102106/1&agg=rss Alla S. Ovcharova<br/> We consider a deformation and a rupture of a thin liquid film which is hanging between two solid flat walls under the action of concentrated thermal load action. A two-dimensional model is applied to describe the motion of thin layers of viscous non-isothermal liquid under micro-gravity conditions. ... [Phys. Fluids 23, 102106 (2011)] published Fri Oct 21, 2011. Inertial modes of a periodically forced buoyant drop attached to a capillary http://link.aip.org/link/?PHF/23/102104/1&agg=rss Nicolas Abi Chebel, Frederic Risso, and Olivier Masbernat<br/> A drop of heptane attached to a capillary tip immersed in water is submitted to small amplitude volume oscillations. Its interface is imaged by means of a high-speed camera and its shape decomposed into spherical harmonics. The forcing frequency is varied over a large range including the frequencies ... [Phys. Fluids 23, 102104 (2011)] published Wed Oct 19, 2011. Bubble dynamics atop an oscillating substrate: Interplay of compressibility and contact angle hysteresis http://link.aip.org/link/?PHF/23/102105/1&agg=rss Irina S. Fayzrakhmanova, Arthur V. Straube, and Sergey Shklyaev<br/> We consider a sessile hemispherical bubble sitting on the transversally oscillating bottom of a deep liquid layer and focus on the interplay of the compressibility of the bubble and the contact angle hysteresis. In the presence of contact angle hysteresis, the compressible bubble exhibits two kinds ... [Phys. Fluids 23, 102105 (2011)] published Wed Oct 19, 2011.