Roman De Giuli’s short film “Stream” explores a macro world of color and flow, with a few glimpses behind-the-scenes at how the visuals get made. The artistic canvas here is a glass plate; the materials are oil, ink, and water. As simple as the ingredients are, though, the view is complex and enchanting. It’s amazing to see just how much goes on in an area the size of one’s thumb. (Image and video credit: R. De Giuli)
Light streams from the branches of trees in this series from photographer Vitor Schietti. The effect is created with a combination of fireworks, long-exposure photography, and compositing. I love how the falling sparks create streaklines just like so many flow visualization diagnostics do! Follow more of Schietti’s work on Instagram. (Image credit: V. Schietti; via Colossal)
Metallic paint flows like silver lava in this macro video from Chemical Bouillon. The paint has been mixed with an unknown fluid (my guess is alcohol) to produce the flows we see here. My suspicion is that we’re seeing solutal convection where variations in surface tension create convective flow within the liquid. What do you think? (Video and image credit: Chemical Bouillon)
When bodies of water meet, they don’t always mix right away. Here we see the confluence of the Back and Hayes Rivers in the Canadian Arctic. The Back River appears as a darker blue-green color compared to the light turquoise Hayes River. The different colors reflect the levels of algae and sediment carried in their waters. As seen in both the aerial and satellite photos here, there’s a distinct line where the two waters meet without mixing, and that line persists for kilometers beyond their initial confluence. Typically, this lack of mixing between bodies of water is caused by differences in temperature, salinity, and turbidity (amount of sediment) that make the density of each river’s water different. (Image credit: top – R. Macdonald/Univ. of Manitoba, bottom – J. Stevens/USGS; via NASA Earth Observatory)
Nothing says, “Goodbye, winter!” quite like watching the ice disappear after a deep freeze. This timelapse video shows ice on Lake Michigan breaking up after a deep freeze. The first chunk to go is a massive plate of ice that moves off in a single large chunk. After that, the break-up takes place on a smaller scale, with individual pieces of ice tracing the flow of local currents. (Video and image credit: WGN News; submitted by ajhir)
Water and sediments swirl in these enhanced satellite photos of China’s Leizhou Peninsula. Color-filtering algorithms have drawn out the details of the flows, but the patterns themselves are real. Tides, currents, sediment, and human activity combine to form these complex flows along the peninsula’s shores. The straight parallel lines seen off Liusha Bay, for example, are likely the result of a traditional fishing method using nets suspended off poles anchored into the seabed. (Image credit: N. Kuring; via NASA Earth Observatory)
When a tire spins over a wet roadway, pressure at the front of the tire generates a lifting force; if that lift exceeds the weight of the car, it will start hydroplaning. To prevent this, the grooves of a tire’s tread are designed to redirect the water. Now researchers have visualized flow inside these grooves for the first time, using a version of particle image velocimetry (PIV). PIV techniques use fluorescent particles to track the flow.
The results reveal a complicated, two-phase flow inside the tire grooves. As seen in the images above, bubble columns form inside the tire grooves. The team’s results suggest that the bubble columns depended on groove width, spacing, and intersections with other grooves. They also saw evidence of vortices inside some grooves. (Image credit: tires – S. Warid, others – D. Cabut et al.; research credit: D. Cabut et al.; via Physics World; submitted by Kam-Yung Soh)
In “Geodaehan” Roman De Giuli’s macro fluid art mimics massive landscapes. The film takes us over deltas, rivers, glaciers, and landslides. Some look like earthbound locations, others look like something from Mars or Titan. All are, in fact, paint, ink, and glitter on paper! It’s truly incredible how artists capture large-scale fluid physics on such a tiny canvas. (Image and video credit: R. De Giuli)
For more than a century, scientists have been fascinated by the jet that forms after a drop impacts a liquid. In this study, researchers tracked fluorescent particles in the fluid to understand the velocity and acceleration of flow inside the jet. They found that, within the first 10ms after the jet appears, it decelerates at up to 20 times the gravitational acceleration. That’s much too fast for gravity to cause, pointing instead to the critical importance of surface tension in dictating the behavior of these fast-moving jets. (Image and research credit: C. van Rijn et al.; via APS Physics; submitted by Kam-Yung Soh)
As a bubble sitting on a pool collapses, wrinkles form around its edges. Visually, the result is quite similar to the wrinkles one gets on an elastic sheet. Unlike the solid sheet, though, the bubble’s film varies in thickness; we know this because of the fringes shown in the enlarged inset of the poster. Researchers are studying this non-uniformity to see whether it affects the number and shape of wrinkles that form on the bubble. (Image and research credit: O. McRae et al.)