FYFD

Tag: flow visualization

  • Aerosols and Instruments

    Aerosols and Instruments

    Although COVID has disrupted all of our lives, orchestras saw particular disruption, as little was known about how instruments spread aerosol droplets. In this recent study, a team looked at many wind instruments, as played by professional musicians, for the aerosol load and air flow each instrument creates. They found that, on the whole, wind instruments — like flutes, clarinets, trumpets, and others — create aerosol loads comparable to normal speech. The air flow from each instrument comes primarily from the bell (for brass instruments) or tone holes (for woodwinds) and has a much lower velocity than coughing or sneezing. As a result, the flow decays away to the background air-flow after about 2 meters. (Image credit: trumpet – E. Awuy, trombone – Q. Brosseau et al.; research credit: Q. Brosseau et al.)

    Flow from the bell of a trombone disrupts artificial fog.
    As a musician plays a scale on their trombone, flow from the bell is revealed through artificial fog and laser illumination.
  • “Keeping Our Sheet Together”

    “Keeping Our Sheet Together”

    When two liquid jets collide, they form a falling liquid sheet. Here researchers explore how that sheet breaks up when the liquids involved contain polymers. The intact areas of the sheet show as dark red or almost black. The edges of the sheet appear in brighter red and yellow, outlining the holes that form and grow during breakup. The type of breakup observed depends on the concentration of polymer in the liquid. (Image credit: C. Galvin et al.)

  • Flowers Through a Hazy Veil

    Flowers Through a Hazy Veil

    A smoke-like haze obscures colorful bouquets in these photographs from artist Robert Peek. To achieve the effect, Peek submerges his subjects underwater with white dye that sinks due to its greater density. The wakes traced by the dye are impressively laminar, so the dye must drift rather slowly past each petal. The overall effect is beautifully dream-like. You can find more of Peek’s work on Behance and Instagram. (Image credit: R. Peek; via Colossal)

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    Leaky Resonance

    Some resonators aren’t perfect — nor are they meant to be! Here, researchers experiment with resonance using a disk shaking up and down over a pool of water. The disk never touches the water, but its movement makes the air above the water move in and out, like a miniature, changeable wind. The air flow distorts the water surface, creating waves just tens of microns high. Beneath the disk, the water forms standing waves, indicating resonance.

    But the waves don’t stay under the disk. Beyond its edge, we see traveling waves moving outward, carrying some of the disk’s energy with them. This leakage is actually how many musical instruments, like a guitar, work. When the guitar strings are plucked, their vibrations are transmitted into the body of the guitar through its bridge, where the strings are anchored. The body acts as a resonator, amplifying the sound, some of which leaks out the sound hole. (Image and video credit: U. Jain et al.)

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    Dolphins Playing With Bubble Rings

    Blow a jet of air underwater and you can make a bubble ring. It takes some practice for humans, or you can use a device. In this video, a team introduced wild dolphins to a bubble-ring-making machine and observed how the dolphins reacted. After some initial wariness, the animals played with them for hours, creating games and having fun. Note that there are some dolphins who create their own bubble rings to play with, so it’s hard to say that these particular dolphins have never seen a bubble ring before. But even if they have seen the bubbles, they wouldn’t have seen a machine making them. (Image and video credit: BBC Earth)

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    “Haut”

    In Susi Sie’s “Haut” the camera seems to fly over ever-shifting landscapes. In reality, these are macro images, created (I think) by dyes and patterns atop a water bath. But they look like vistas we could find on Earth or Mars — giant dune fields, calving glaciers, and river-divided canyons. For something similar in color, check out Roman De Giuli’s “Geodaehan.” (Video credit: S. Sie)

  • Jupiter in Infrared

    Jupiter in Infrared

    These recent composite images from the James Webb Space Telescope show Jupiter in stunning infrared detail. They’re the result of several images taken in different infrared bands, then combined and rendered in visible light. In general, the redder colors show longer wavelengths and the bluer ones show shorter wavelengths.

    Jupiter’s cloud bands appear in beautiful detail. The Great Red Spot looks white in infrared. And the planet’s polar auroras shine bright in both images. The wide-angle shot additionally shows two of Jupiter’s moons and the planet’s rings, which are a million times fainter than the planet itself. If you look carefully, you may also see faint points of light in the lower half of the image. These are likely distant galaxies “photobombing” Jupiter’s close-up. (Image credit: NASA/ESA/Jupiter ERS Team 1, 2; via Colossal)

    This composite image of Jupiter was taken in infrared bands and rendered into visible light. In general, the redder colors represent longer wavelengths and bluer ones shorter wavelengths.
    This composite image of Jupiter was taken in infrared bands and rendered into visible light. In general, the redder colors represent longer wavelengths and bluer ones shorter wavelengths.
  • Blooms in the Black Sea

    Blooms in the Black Sea

    The Black Sea gains its name from its dark waters, but those waters don’t stay dark year-round. In this natural color satellite image, streaks of milky blue bloom through the summer waters, thanks to the presence of a species of phytoplankton armored with white calcium carbonate. Despite their microscopic size, the phytoplankton’s presence is visible from space. During other parts of the year, like the spring, another species of phytoplankton dominates the Black Sea, turning its waters darker. (Image credit: J. Stevens; via NASA Earth Observatory)

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    Peering Into the Gap

    This video offers a glimpse into turbulence developing in a classic flow set-up, a Taylor-Couette cylinder. The apparatus consists of two upright, concentric cylinders; the outer cylinder is fixed, and the inner one rotates. This video shows the gap between the cylinders, and it’s rotated so that the inner cylinder is at the bottom of the frame. Gravity points from left to right in the video. The fluid in the 8-cm gap between the cylinders is water, seeded with rheoscopic particles to visualize the flow.

    The video begins as the inner cylinder has just begun to rotate, dragging nearby fluid with it. A thin, laminar boundary layer forms at the bottom of the frame, growing as time goes on. A few seconds in, the boundary layer transitions to turbulence; look closely and you’ll see hairpin-shaped vortices appear. Just after that, the boundary layer becomes entirely turbulent and continues to slowly move upward to take over the full gap. The video is available in a full 4K resolution if you really want to get lost in the flow. (Video credit: D. van Gils)

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    Aerated Faucets

    So much goes on in our daily lives that we never see. But with the power of the smartphones in our pockets, we can catch more than ever before, as illustrated in this video. Here a researcher uses the standard “slo-mo” (240 fps) video mode on a smartphone to look at the flow from a typical kitchen faucet. Household faucets often have an aerator that adds air bubbles to the flow, something that’s particularly visible in slow motion at high flow rates. What you can see depends on more than just the frame rate, though. Without strong illumination — provided in this case by sunlight — you could easily miss the cloud of droplets ejected by the faucet. (Image and video credit: M. Mungal)