Bulletin of the American Physical Society
72nd Annual Meeting of the APS Division of Fluid Dynamics
Volume 64, Number 13
Saturday–Tuesday, November 23–26, 2019; Seattle, Washington
Session G01: Free Surface Flows: Instability and General Topics |
Hide Abstracts |
Chair: Bill Schultz, University of Michigan Room: 2A |
Sunday, November 24, 2019 3:48PM - 4:01PM |
G01.00001: Collapse of multiple holes in an unbounded liquid film Michael Eigenbrod, Steffen Hardt We study experimentally and theoretically the collapse of multiple holes in a liquid film. The time evolution of an ensemble of holes is examined using high-speed videomicroscopy and characterized by the time-dependence of the hole shapes. An analytical formula for the potential energy difference between an unbounded liquid film with $N$ holes and a film without holes is derived based on the Young-Laplace equation, accounting for surface tension and gravity. The equation is valid for small solid-liquid contact angles and arbitrary shapes of the three-phase contact line. It is further suggested that the time evolution of a multi-hole arrangement in a highly viscous film can be predicted through steepest descent of the potential energy in a configuration space representing the shapes of the holes. The theoretical model for the time evolution of the system if confirmed by experimental results for the collapse of multiple nearly circular holes. [Preview Abstract] |
Sunday, November 24, 2019 4:01PM - 4:14PM |
G01.00002: Thermal rupture of a free liquid sheet Jens Eggers, Georgy Kitavtsev, Marco Fontelos We consider a free liquid sheet, taking into account the dependence of surface tension on the temperature or concentration of some pollutant. The sheet dynamics are described within a long-wavelength description. In the presence of viscosity, local thinning of the sheet is driven by a strong temperature gradient across the pinch region, resembling a shock. As a result, for long times the sheet thins exponentially, leading to breakup. We describe the quasi-one-dimensional thickness, velocity and temperature profiles in the pinch region in terms of similarity solutions, which possess a universal structure. Our analytical description agrees quantitatively with numerical simulations. [Preview Abstract] |
Sunday, November 24, 2019 4:14PM - 4:27PM |
G01.00003: Optimal Capillary Breakup Rheometer Procedures for Newtonian Filaments Subramaniam Balakrishna, William Schultz The differential analysis of McCarroll et al (2016) determines the surface tension to viscosity ratio from the symmetry point of an unsteady Newtonian filament profile and its derivatives. The experimental challenges are twofold: (a) the fourth derivative of the free surface radius is required and difficult to extract from low-resolution, pixelated and possibly noisy images and (b) the sensitivity of the surface tension to viscosity ratio to the stretch history. In particular, for filament evolution dominated by viscosity and surface tension, stretching too quickly makes the free surface profile nearly cylindrical, while stretching too slowly yields a quasi-static profile with no viscous information.~ We give strategies that optimize the ratio measurement including use of higher-order finite difference stencils and measurements made during stretch. [Preview Abstract] |
Sunday, November 24, 2019 4:27PM - 4:40PM |
G01.00004: ABSTRACT WITHDRAWN |
Sunday, November 24, 2019 4:40PM - 4:53PM |
G01.00005: Interfacial perturbation classification of a fluid impulsively driven through a honeycomb mesh into a gas-filled cavity Takiah Ebbs-Picken, Rubert MartÃn Pardo, David Plant, Andrew Higgins, Jovan Nedic We investigate the development of perturbations on a liquid-gas interface created by the impulsive motion of fluid through a honeycomb mesh. The effects of implosion speed, mesh geometry, angular velocity of the interface, and initial liquid depth relative to the mesh were experimentally investigated to determine their effects on the geometry of the perturbations formed. An experimental arrangement was created that allowed for the visualization of the cavity surface, and a classification based on the perturbation geometry was developed. Five different perturbations were observed, which were classified as follows: none, wavy, sharp, jetting and complex. The results showed that the parameter which had the largest impact on the initial perturbation growth was the fill depth of the liquid relative to the mesh, while the angular velocity and implosion speed had limited effects. [Preview Abstract] |
Sunday, November 24, 2019 4:53PM - 5:06PM |
G01.00006: The natural breakup length of a steady capillary jet Sasa Bajt, Henry Chapman, Max Wiedorn, Juraj Knoska, Yang Du, Michael Heyman, Braulio Ganan-Riesco, Jose M. Lopez-Herrera, Miguel A. Herrada, Francisco Cruz-Mazo, Alfonso M. Ganan-Calvo The averaged natural breakup length of capillary jets ejected in inactive environments are determined by the liquid properties, its velocity and its diameter. Despite its theoretical and applied interest, a general procedure to predict that length has not been proposed yet. Here we describe and quantify the energy route that sets it. We find that the underlying mechanism that determines that length is the short-term transient growth rate of perturbations excited by the jet breakup itself. We propose a perturbation analysis of the time averaged energy conservation equation in the absence of body forces. The balance of total energy rates due to the perturbations is reduced, by dimensional analysis, to a closed algebraic expression with two universal constants. These constants are calculated by optimal fitting of a large set of experiments from diverse sources, experimental and numerical, which confirm the universal scaling law found. [Preview Abstract] |
Sunday, November 24, 2019 5:06PM - 5:19PM |
G01.00007: Modelling of perturbations in the surface of a cylindrical imploding rotating cavity. Rubert Martin Pardo, David Plant, Jovan Nedic A cylindrical cavity is formed by rotating a liquid to solid body rotation resulting in a cylindrical liquid shell surrounding a gas-filled cavity. As this cavity is radially collapsed by pushing the fluid through a honeycomb mesh, perturbations begin to form on the interface. The dynamics of this perturbation can be well modelled by a second-order ODE and, as such, the initial velocity and amplitude of the perturbation have a decisive role on the ulterior behavior of the roughness of the surface during the implosion. It will be shown how this initial perturbation, in turn, depends on different control parameters, namely the driving pressure profile, the rotation rate of the system, the initial liquid depth and the mesh geometry. A model is developed to account for this relation. The cavity surface was measured using high-speed videography and surface tracking digital techniques for a range of values of the control parameters sufficient to capture the change from a rough cavity surface to a smooth interface. [Preview Abstract] |
Sunday, November 24, 2019 5:19PM - 5:32PM |
G01.00008: The healing of a viscous annular thread and formation of an entrained bubble- fingerprints of dripping of a viscous film Fan Yang, Howard Stone We focus on a generic type of dripping- dripping of a viscous annular thread- that is not well-studied. Unlike conventional jet or droplet dripping, which forms a cylindrical liquid column, we study experimentally and theoretically configurations that lead to the formation of a liquid annulus in the initial stage of film dripping. Then the annulus heals due to surface tension and the inner surface forms a retracting cusp. We document that the shape of the cusp is universal and the retraction speed is determined by the balance of viscous and capillary stresses. During the healing process, air is driven into the droplet and consequently forms an entrained bubble. A one-dimensional model is applied to analyze the healing dynamics, which shows good agreement with experiment measurements. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700