The Division of Fluid Dynamics exists for the advancement and diffusion of knowledge of the physics of fluids with special emphasis on the dynamical theories of the liquid, plastic and gaseous states of matter under all conditions of temperature and pressure.

Every year, the APS Division of Fluid Dynamics hosts a physical Gallery of Fluid Motion at its annual meeting—a room where stunning graphics and videos from computational or experimental studies showing flow phenomena are displayed. The most outstanding entries are selected by a panel of referees for artistic content and honored for their originality and ability to convey information. Past winners are published in the journal.
Physics of Fluids

In conjunction with the 65th Annual Meeting of the American Physical Society (APS) Division of Fluid Dynamics (November 18-20, 2012, San Diego, California), a subset of these images and videos is archived on the APS DFD website.
  APS DFD Virtual Press Room Archives

Usage Permission

Reporters seeking permission to use these images or author contact information should email Charles Blue. Please leave "DFD Gallery of Fluid Motion" in the subject line.

Flow Visualization of Annular Liquid Sheet Instability & Atomization

Daniel Duke
Damon Honnery
Julio Soria
Laboratory for Turbulence Research in Aerospace & Combustion
Dept. Mechanical & Aerospace Engineering
Monash University
Australia

These videos show a thin sheet of liquid studied by using a high-speed video camera and a high-speed pulsed light source. A complex instability is formed by concurrently encapsulating the outer and inner surfaces of the fluid with a stream of fast-moving gas.
   Annular Liquid Sheet 

Droplets Bouncing Over a Vibrating Fluid Layer

Pablo Cabrera-Garcia
Roberto Zenit
Universidad Nacional Autónoma de México

This video shows a technique to prevent droplet coalescence, in which droplets dropped onto a liquid surface lose their shape and fuse with the liquid. By vibrating the liquid surface, the drops can remain suspended indefinitely. Clusters of many droplets are formed. The size of the clusters is controlled by the strength of vibration, with stronger vibrations maintaining larger clusters.
  Bouncing Droplets 

Spontaneous Capillarity-Driven Droplet Ejection

Andrew Wollman
Mark Weislogel
Portland State University

Trevor Snyder Xerox Inc.

Donald Pettit NASA, Johnson Space Center

In 1957 it was observed that even in the absence of gravity, a capillary flow through a tube halts when it reaches the end of the tube. Although the fluid partially left the tubes in these experiments, it was always pulled back by surface tension, which caused the fluid to remain pinned to the tube's end. However, new tests demonstrate that such flows in tapered tubes are capable of a variety of passively propelled liquid jets and droplets. This video provides a historic overview of such auto-ejections in normal and microgravity environments.
  Capillarity-Driven Droplet 

Stability of Capillary Surfaces Supported by a Helical Wire

 

Jorge A. Bernate
Stanford University

David B. Thiessen
Washington State University

Unsupported, a column of liquid breaks when its length exceeds a critical value. But a helical wire can stabilize the column for an infinite length. A given extension of the helical wire can support columns with a range of stable volumes. This video shows issues related to the injection of liquid into the helical wires, the instabilities that occur beyond the limits of the stable range, and the fate of the liquid column after these instabilities occur.
  Helical Wire 

How to Freeze Drops with Powder

Jeremy Marston
Ying Zhu
Ivan Vakarelski
Siggi Thoroddsen
King Abdullah University of Science and Technology

This video shows that when a drop of water impacts a powder, such as glass beads, it can rebound with a partial coating of powder. However, if the powder is superhydrophobic, the drop rebounds with a powder coating that "freezes" the shape of the droplet, producing deformed (non-spherical) shapes.
  Freeze Drops 

3D Shock-Bubble Interactions at Mach 3

Babak Hejazialhosseini
Diego Rossinelli
Petros Koumoutsakos
Eidgenössische Technische Hochschule Zürich
Switzerland

This video shows a computer simulation of a Mach 3 normal shock wave in air that is directed at a helium bubble. As the shock wave passes over the bubble, the bubble is compressed; the interface between bubble and air is deformed due to the generation of vorticity on this interface; a jet of air shoots out; and a long-lasting vortical core develops followed by a complex mixing zone. The software enables simulations using up to 250 billion cells on a supercomputer, and 4 billion cells were used to produce this visualization.
  Shock-Bubble 

Diving with Microparticles in Acoustic Fields

Alvaro Marin
Massimiliano Rossi
Christian Kaehler
Universitat der Bundeswehr Munchen

Rune Barnkob
Peter Muller
Henrik Bruus
Technical University of Denmark

Per Augustsson
Thomas Laurell
Lund University

A popular science demonstration is to create a standing acoustic wave on a plate known as a Chladni plate. The standing wave causes minute particles to migrate to the vibration nodes, or points where the waves cancel. This video demonstrates that a similar phenomenon can occur in three dimensions for microparticles suspended in water with an imposed standing ultrasonic wave, and that by using advanced visualization techniques we can actually "dive" with the microparticles that stream in circles under the action of the acoustic waves.
  Microparticles in Acoustic Fields 

Inside a Kettle

S. Wildeman
H. Lhuissier
C. Sun
D. Lohse
University of Twente
Netherlands

This video shows what happens when a watched pot eventually boils. A warm layer of liquid forms above the hot plate and heat plumes begin to rise. Eventually the liquid starts to boil. When bubbles detach, they drag hot liquid to the surface which facilitates heat transport. But if the bubbles coalesce to form an insulating layer of vapor between the hot plate and the liquid, the boiling slows down.
  Inside a Kettle 

Rayleigh-Taylor Instability between Two Stable Stratifications

Megan S. Davies Wykes
Stuart B. Dalziel
University of Cambridge
England

This video shows two experiments in which liquids of varying density are mixed by a fluid instability. In the first experiment, the instability creates a mixing region, the growth of which accelerates with time until it fills the entire tank. In the second experiment, the instability is confined by a stable density stratification and grows more slowly, bringing the growth of the mixing region to a halt before it fills the entire tank.
  Rayleigh-Taylor Instability 

Jets from Hollows

Thomas Seon
Elisabeth Ghabache
Arnaud Antkowiak
Institut d' Alembert, UPMC & CNRS
Paris, France

This video shows the gravity-driven jets produced by the relaxation of large elongated bubbles and holes at the free surface of a liquid. The jets developing inside a bubble can be strong enough to create liquid projections shooting out far above the surface.
  Jets from Hollows 

Siquieros Accidental Painting Technique: A Fluid Mechanics Point of View

Sandra Zetina
Roberto Zenit
Universidad Nacional Autónoma de México

This video shows an analysis of the "accidental painting" technique developed by Mexican muralist D.A. Siqueiros. The technique of pouring one layer of paint on top of another was recreated and studied. It was found that when the top layer is denser than the lower one, the viscous current becomes unstable as it spreads radially. As the layers spread and mix, they create aesthetically pleasing patterns.
  Siquieros Accidental Painting Technique 

Surface Explosion Cavities

Adrien Benusiglio Christophe Clanet
École Polytechnique
Cedex, France

David Quéré
PMMH – ESPCI
Paris, France

This video shows air cavities created by explosions of firecrackers at the water surface. Without confinement, the explosion produces a hemispherical cavity that rapidly expands. The bottom of the cavity then accelerates backwards to the surface, creating a central jet that rises above the surface. In the last part of the video, the explosion is confined in a vertical open tube made of glass. The explosion creates a cylindrical cavity that develops toward the free end of the tube. Depending on the charge, the cavity can either stop inside the tube or at its exit, but it never escapes.
  Surface Explosion Cavities