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Search results for: “vortex”

  • “Opening the Vortex”

    “Opening the Vortex”

    Photographer Lisa K. Kuhn captured a spectacular lenticular cloud over Mount Shasta in this image from the Sony World Photography Awards. These lens-shaped clouds occur most often near mountains and other terrain that forces air to flow up and over it. As the air cools, water condenses out, forming the cloud. When the air flows down and warms, condensation is no longer possible. The end result is a cloud that appears stationary against the mountain, even though air is continuously moving past. Add in the long sun angles and beautiful colors of near-sunset and the results are incredible. (Image credit: L. Kuhn; via Colossal)

    A spectacular lenticular cloud over Mount Shasta near sunset. Photo by Lisa K. Kuhn.
  • Viscoelastic Vortex Street

    Viscoelastic Vortex Street

    When flow moves past a cylinder, vortices get shed in its wake. Known as a von Karman vortex street, this distinctive pattern is seen behind flags, islands, and even behind starships. Here, researchers are simulating flow of a viscoelastic fluid, where–unlike water or other Newtonian fluids–elastic stresses can build up.

    As the flow hits the leading edge of the cylinder, the polymers in the fluid compress and then get stretched as the flow moves around the cylinder. The left image shows vorticity in the flow; the right shows elastic stresses. The large swirls are primary vortices–those shed off the cylinder. But look closely and you’ll see smaller secondary vortices curled up beside the primaries. These form when the elastic stresses in the fluid pull some of the shear layer into the wake. (Image and research credit: U. Patel et al.)

    Simulation of a flow around a cylinder in a viscoelastic flow. Left, vorticity; right, elastic stresses.
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    “Magnetic Vortex”

    The Macro room team is back with a video featuring their signature colorful cleverness. This time they’re using a magnetic stirrer to swirl up some mesmerizing flows. It’s well worth a watch. (Video and image credit: Macro Room)

    Fediverse Reactions

  • Magnetic Vortex

  • Vortex Rings at Dawn

    Vortex Rings at Dawn

    Vortex rings blown from Mount Etna’s vents drift through the dawn light in this beautiful image from Dario Giannobile. Little is required to create vortex rings — they are a puff of fluid shaped by an orifice — but they are relatively unusual to see around volcanoes. Etna is an exception; it happens to have one or more vents that frequently form rings. Their shape and the venting pattern of the volcano must be unusually well-suited to ring formation. (Image credit: D. Giannobile; via APOD)

  • Vortex Below

    Vortex Below

    When a drop of ethanol lands on a pool of water, surface tension forces draw it into a fast-spreading film. Evenly-spaced plumes form at the edges of the film, then the film stops spreading and instead retracts. All of this takes place in about 0.6 seconds. But, as the image above shows, there’s more that goes on beneath the surface. A vortex ring forms and spreads under the film, driven by the shear layer under the edge of the plumes. Here, the vortex ring is visible in the swirling particles near the water surface. (Image and research credit: A. Pant and B. Puthenveettil)

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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.)

  • Draining By Vortex

    Draining By Vortex

    Unstop your bathtub and the draining water will form a tiny tornado-shaped vortex over the outlet. Four centuries ago Torricelli developed a mathematical equation to describe how long it would take to empty the container, based on the height of the fluid in the tank. Now researchers have made a more generalized version of Torricelli’s law, based on experiments with a rotating tank. They found that measuring the water level above the outlet (i.e., taking into account the surface level dip caused by the vortex) gave better agreement. The stronger the vortex, the lower the surface dips and the slower the container drains. (Image and research credit: A. Caquas et al.)

  • Washing By Vortex Ring

    Washing By Vortex Ring

    Spraying a surface clean with a jet of fluid can be an energy-intensive operation. But a recent experiment shows that pulsed flow — which creates vortex rings — could be a viable cleaning alternative. Here we see vortex rings impacting a porous, beaded surface that’s covered in oil. Vortex rings with lots of rotation actually pass through the beads, knocking oil off both the front and back surfaces (Image 1). Even with a lower rotation rate, a vortex ring can still help clean the upper surface (Image 2). (Image and research credit: S. Jain et al.; via APS Physics)

  • Washing By Vortex Ring

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