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Search results for: “drag”

  • Peloton Drag

  • Dragonfly Hovering

  • Titan’s Dragonfly

    Titan’s Dragonfly

    Last week, NASA announced its next New Frontiers mission: a nuclear-powered drone named Dragonfly heading to Titan. This astrobiology mission is set to search our solar system’s second largest moon for signs of life. It’s exciting aerodynamically, as well, since Titan’s thick atmosphere makes it uniquely suited for heavier-than-air flight. Therefore, rather than using wheeled rovers like we have on Mars, Dragonfly is a rotorcraft. It will be capable of traveling up to 8km per flight, which will quickly surpass the fewer than 21km the Curiosity Rover has managed on Mars! 

    Like Earth, Titan has rainfall and open liquid bodies on its surface. I, for one, can’t wait to see the alien vistas Dragonfly sends back as it cruises over methane lakes. (Image and video credit: NASA)

  • Reshaping the Wake to Decrease Drag

    Reshaping the Wake to Decrease Drag

    When it comes to the aerodynamics of cars, there’s only so much streamlining one can do. In the end, most cars have a certain boxy-ness as a matter of practicality; they do, after all, have to carry people and things. But that doesn’t mean we’re stuck with the level of drag those shapes entail.

    For cars and other non-streamlined objects, much of their drag comes from their wake, which usually contains a large, asymmetric, and unsteady recirculation region. In a new wind tunnel study, scientists used air blasts to reshape this wake, making it more symmetrical, even when the wind direction did not align with the car model. That reduced the drag by 6%. They’re now experimenting with adding additional nozzles along the non-windward edges of the model to see if they can reduce drag even further.

    Although this appears to be the first time this technique has been tested for road vehicles, the idea of blowing air to improve aerodynamics is well-established, particularly in aviation. (Image credit: V. Malagoli; research credit: R. Li et al., submitted by Marc A.)

  • Reducing Drag with Bubbles

    Reducing Drag with Bubbles

    Large ships experience a great deal of drag due to friction between their hull and the water. One method shipbuilders are considering to combat this drag is the use of bubbles, which have been found to reduce drag by up to 40%. The physical mechanism behind this drag reduction is not yet understood, but a recent study suggests that bubble size and bubble coalescence play an important role.

    Researchers introduced surfactants into bubbly boundary layers and found that the reductions in drag evaporated as soon as the surfactants spread. Adding only 6 parts per million of the surfactant decreased average bubble size from 1 mm to 0.1 mm and helped prevent the bubbles from growing via coalescence. The implications are that bubble-induced drag reduction could be extremely sensitive to water conditions. (Image credit: G. Kiss; research credit: R. Verschoof et al.)

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    Plucking Droplets

    A sudden breeze can pluck droplets hanging from a stem. Here, researchers recreate that phenomenon in the laboratory. With a close-up view and high-speed images, we can enjoy every detail of the detachment and break-up. As the wire pulls away, it drags a liquid sheet off the droplet. The thicker rims on either side of the sheet eventually collide, creating a jet that stretches, deforms, and, at last, breaks. (Video and image credit: D. Maity et al.)

    Animation of two droplets getting plucked, one made of glycerin+water (left) and one of water (right).
    Animation of two droplets getting plucked, one made of glycerin+water (left) and one of water (right).
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  • Aflutter in the Breeze

    Aflutter in the Breeze

    Fabrics flutter in seemingly impossible ways in artist Thomas Jackson‘s images. But despite first appearances, each photograph is true to life; the fabrics are suspended on taut lines. Their dance is driven by wind energy, drag, tension, and flow–not manipulated pixels. I love the (turbulent) energy of them! (Image credit: T. Jackson; via Colossal)

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  • Milano Cortina 2026: Ski Jumping Suits

    Milano Cortina 2026: Ski Jumping Suits

    Ski jumping is in the news this Olympic cycle after rumors that male competitors may be cheating in order to wear larger suits. In particular, the suggestion is that male athletes are injecting fillers into their genitals before their pre-season 3D body scan in order to appear large enough to allow them to wear a larger suit. This comes after two Norwegian ski jumpers were punished for illegally restitching the crotches of their suits to make them larger.

    Ski jumping is a sport that relies heavily on aerodynamics; during the flight phase, jumpers try to maximize their lift-to-drag ratio so that they stay aloft as long as possible. A 2025 study underscores the importance of suit size in this calculus. In the work, the researchers used a baseline suit that was 4 centimeters larger in circumference than their jumper–the loosest configuration that regulations allow. They compared that suit’s flight performance (in wind tunnels and simulation) to a suit 2 cm larger and one 2 cm smaller. The extra 2 centimeters of circumference made a notable difference: the larger suit increased the drag by ~4% and lift by ~5%. That was enough, in their simulation, to let a jumper fly an extra 5.8 meters.

    It’s worth noting, though, that the study was looking at the effects of adjusting the suit’s circumference along the entire length between the arm pits and the knees; they never changed anything about the suit’s crotch. I don’t think there’s enough scientific data to say that packing a bit more there would really offer aerodynamic advantages. And the risks of such injections are non-negligible. (Image credit: T. Trapani; research credit: M. Virmavirta et al.; via Ars Technica)

    A ski jumper in flight, viewed from behind.
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    Wavy Water Entry

    When an object like a sphere enters the water, it drags air into the water behind it, creating a cavity. Depending on the sphere’s impact speed, the cavity might close first under the water, forming a deep seal, or at the surface with a surface seal. But, as this video points out, water often isn’t still. Here, they explore how the sphere’s entry changes when there are ripples on the water surface. (Video and image credit: M. Ibrahim et al.; via GFM)

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    Leaves Dance in the Wind

    Once a breeze kicks up, leaves on a tree start dancing. Every tree’s leaves have their own shapes, some of which appear very different from other trees. But their dances have patterns, as this video shows. In it, researchers explore how leaves of different shapes deform in the wind and how they can decompose that motion to compare across leaves. (Video and image credit: K. Mulleners et al.; via GFM)

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