FYFD

Tag: flow visualization

  • Featured Video Play Icon

    Visualizing Changes

    This rather mesmerizing video by Michiel de Boer uses a video editing technique to highlight movement and changes in video clips. From falling rain to rising mist to passing footsteps, the relatively simple technique visualizes all kinds of motion. De Boer calls it “motion extraction,” but it’s essentially a way to play with autocorrelation, a mathematical technique often used in fluid dynamics. It’s especially prevalent in turbulence, where it helps researchers identify parts of the flow that are closely related to one another. (Video and image credit: M. de Boer; via Colossal)

  • Parting a Flame

    Parting a Flame

    A sheet of flame splits around a cylinder in this Gallery of Fluid Motion poster. Looking at the image sequences, you can see how the flames lift up as they flow around the cylinder, following the arms of a horseshoe vortex. Researchers study situations like this one to better understand how wildfires move as they encounter obstacles. Understanding and predicting how fires flow is increasingly important with more wildfires encountering human-built infrastructure. (Image credit: L. Shannon et al.)

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    Vortex Rings From a Square Outlet

    When a vortex ring forms, it’s often from fluid forced through a round outlet, whether that’s someone’s mouth, a pipe, or a dolphin’s blowhole. But vortex rings can come from other shapes, too. This video shows us several examples, including slots and square outlets. The vortex rings blown from a square outlet are messier but still recognizable. The slot-shaped outlets produce even neater results, including twin vortex rings that move parallel to one another! (Image, video, and research credit: B. Steinfurth et al.)

  • Corralling Corals

    Corralling Corals

    So much of fluid dynamics is seeking patterns. Shown here are two sets of patterns, each created by a different species of coral larvae. These tiny creatures form a streaming flow (orange inset) around them as they swim. Combined together in a petri dish, the larvae follow winding paths, shown in white. The overall pattern is distinctly different for the two species. One shows a clear preference for paths near the wall of the dish (left), while the other corkscrews through open spaces (right). This difference raises questions researchers can explore: do the larvae differ in their propulsion methods or in their collective behavior? (Image credit: G. Juarez and D. Gysbers)

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    Liquid Lace

    3D printers are a neat apparatus for exploring flow instabilities. If too much material is extruded compared to the speed of the printer head, coiling takes place. But under-extrusion creates patterns, too. Here, researchers show how under-extrusion can create a stable lace-like pattern. Once dried, the material can stretch, but only in certain directions, a bit like many textiles. (Video and image credit: L. Dreier et al.)

  • Thermal Slipping

    Thermal Slipping

    A particle suspended in a liquid typically jitters haphazardly about as it’s struck randomly by nearby liquid molecules. But when a temperature gradient is applied to the liquid, that random motion instead becomes directional. In a recent study, researchers directly mapped the motions underlying this thermophoresis.

    In their experiment, the team placed a 7-micron sphere in water laced with 500-nanometer fluorescent tracers. Using a laser, they optically trapped the sphere, pinning it in place. Then, with a second laser, they heated the water on one side of the sphere and observed, under a microscope, what happened. After a few seconds, the tracers began moving toward the hot region, creating a slip flow along the surface of the sphere. Had the sphere been able to move freely, they found, the flow would have been strong enough to move it. (Image and research credit: T. Tsuji et al.; via APS Physics)

  • Inside a Soap Bubble

    Inside a Soap Bubble

    Every child learns to blow soap bubbles, but it’s rare that we have a chance to look inside them and see the flow there. In this poster, researchers seed a growing bubble with olive oil droplets, then illuminate them with a laser. This provides a glimpse inside the bubble. In the center, we see the incoming jet dividing the bubble in two and forming two large, counter-rotating vortices. Along the left side, snapshots show the bubble’s interior as it grows and, eventually, pops. (Image credit: S. Rau et al.)

  • Shaking on Impact

    Shaking on Impact

    When objects impact water with enough speed, they create a smooth-walled, air-filled cavity around and behind them. Here, the impacting object is one with some give, like a spring. The initial impact squishes the object, setting it to oscillating along its length. The result is a wavy cavity. The stiffer the object, the more frequent the waves. (Image credit: J. Antolik et al.)

  • The Best of FYFD 2023

    The Best of FYFD 2023

    A fresh year means a look back at what was popular last year on FYFD. Usually, I give a numeric list of the top 10 posts, but this year the analytics weren’t as clear. So, instead, I’m combining from a few different sources and presenting an unordered list of some of the site’s most popular content. Here you go:

    I’m really pleased with the mix of topics this year; many of these topics are straight from research papers, and others are artists’ works. At least one is both. From swimming bacteria to star-birthing nebulas, fluid dynamics are everywhere!

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    (Image credits: sphinx – S. Boury et al., ear model – S. Kim et al., maze – S. Mould, dandelion – S. Chaudhry, water tank – P. Ammon, e. coli – R. Ran et al., drop impact – R. Sharma et al., Leidenfrost – L. Gledhill, toilet – J. Crimaldi et al., engine sim – N. Wimer et al., rivers – D. Coe, fin – F. Weston, snake – P. Schmid, nebula – J. Drudis and C. Sasse, flames – C. Almarcha et al.)

  • Flipping Ice

    Flipping Ice

    In nature ice is ever-changing — growing, shrinking, and shifting. This poster illustrates that with a cylinder of ice floating in room temperature water. As the ice melts, it flips over into a new orientation, stays that way for a time, and then shifts again, as seen in the series of blue images. This flipping results from the melting flows around the ice, illustrated in the colorful central photo. This color schlieren image shows dense plumes of cold meltwater sinking beneath the ice. As that cold water drips down the sides of the ice, it leaves behind a wavy, patterned surface. Eventually, melting from the bottom of the ice leaves the remaining ice top-heavy, which triggers a flip into a more stable orientation. (Image and research credit: B. Johnson et al.)