FYFD

Tag: shockwave

  • Gigapixel Supernova

    Gigapixel Supernova

    Eleven thousand years ago, a star exploded in the constellation Vela, blowing off its outer layers in a spectacular shock wave that remains visible today. Today’s image is a piece of a 1.3-gigapixel composite image of the supernova remnant, captured by the Dark Energy Camera of the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile. Below is a labeled version of the image, identifying the original star — now a fast-spinning pulsar that packs our sun’s mass into an object only kilometers across — its shock wave, and other features. To explore the full-sized image, see NOIRLab. (Image credit: CTIO/NOIRLab/DOE/NSF/AURA; via Colossal)

    A labeled version of the image shows the shock wave and other features.
    A labeled version of the image shows the shock wave and other features.
  • Simeis 147

    Simeis 147

    Sometimes known as the Spaghetti Nebula, Simeis 147 is the remnant of a supernova that occurred 40,000 years ago. The glowing filaments of this composite image show hydrogen and oxygen in red and blue, respectively. These are the outlines of the shock waves that blew off the outer layers of the one-time star within. What remains of that star’s core is now a pulsar, a fast-spinning neutron star with a solar wind that continues to push on the dust and gas we see here. (Image credit: S. Vetter; via APOD)

  • Lasers and Soap Films

    Lasers and Soap Films

    Soap films are a great system for visualizing fluid flows. Researchers use them to look at flags, fish schooling and drafting, and even wind turbines. In this work, researchers explore the soap film’s reaction to lasers. When surfactant concentrations in the soap film are low, laser pulses create shock waves (above) in the film that resemble those seen in aerodynamics. The laser raises the temperature at its point of impact, lowering the local surface tension. That temperature difference triggers a Marangoni flow that draws the heated fluid outward. The low surfactant concentration gives the soap film relatively high elasticity, and that allows the shock waves to form.

    In contrast, a soap film with a high concentration of surfactants has relatively little elasticity. In these films (below), the laser creates a mark that stays visible on the flowing soap film. This “engraving” technique could be used to visualize flow in the soap film without using tracer particles. (Image and research credit: Y. Zhao and H. Xu)

    When surfactant concentrations are high, a laser pulse "engraves" spots onto a flowing soap film. Shown in terms of interference (left) and Schlieren (right) imaging.
    When surfactant concentrations are high, a laser pulse “engraves” spots onto a flowing soap film. Shown in terms of interference (left) and Schlieren (right) imaging.
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    Can Explosions Deflect Bullets?

    In one of their most Mythbusters-like videos ever, the Slow Mo Guys ask: can an explosion deflect a bullet? To find out, they built out a system to trigger a C4 explosive using a 9mm bullet, all while watching with a series of high-speed cameras. As you’d expect, there are lots of blast waves and neat flame propagation to watch. As for the fundamental question, well, you’ll have to watch to find out! (Video and image credit: The Slow Mo Guys)

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    Test Firing a Rocket Engine

    Watching a rocket engine start up in slow motion is always fun. This Slow Mo Guys video shows a test fire of one of Firefly’s engines, which is capable of 45,000 pounds of thrust. Gav walks us through the process of preparing to film the test as well as what his footage shows.

    Green flames mark ignition of the initial fuel, and bursts of flame jerk back and forth as shock waves pass through the engine. That’s a necessary part of establishing supersonic flow through the bell-shaped diffuser at the end of the engine. Once the exhaust reaches supersonic speeds, expelling it creates a diamond-like pattern of standing shock waves and expansion fans that ultimately equalize the exhaust jet’s pressure to that of the surrounding atmosphere. (Video and image credit: The Slow Mo Guys)

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    Withstanding Rocket Launches

    It takes a lot of power to lift a giant rocket‘s payload all the way to orbit, and in the first moments of a rocket launch, all that energy is directed downward at a concrete pad. How do engineers design and protect launch pads? In this Practical Engineering video, Grady tackles just that question through a comparison of SpaceX’s Stage Zero and NASA’s Launch Pad 39A.

    SpaceX notoriously chose to build Stage Zero without a trench or water sprayer system like the ones NASA use. Trenches deflect the rocket exhaust to reduce the impact on infrastructure beneath the engines. And water sprayers reduce the temperatures the pad experiences and disrupt shock waves that otherwise hammer the pad. Without those precautions, even special heavy-duty concretes have a hard time holding together against a launch. (Video and image credit: Practical Engineering)

  • Star YY Hya

    Star YY Hya

    A team of professional and amateur astronomers discovered and then imaged this previously undiscovered galactic nebula. At the heart of the stellar remnant is a binary star pair. Shock waves of the gas and dust twist and spread in the surrounding space, the remains of an earlier star’s violent eruption. (Image credit: M. Drechsler et al.; via 2023 Astronomy POTY)

  • Exploding a Bubble

    Exploding a Bubble

    In this high-speed video, artist Linden Gledhill ignites a mixture of oxygen and hydrogen contained within a soap bubble. As neat as the video is, I decided to take a closer look at the initial detonation with this animation:

    The ignition sequence within the bubble, slowed down further.
    The ignition sequence within the bubble, slowed down further.

    Even here, it’s hard to appreciate just how fast ignition is; it lasts only a handful of frames, despite filming at 40,000 frames per second. But we can still pick out some very neat physics. The ignition begins with a spike-like jet but immediately forks into three ignition fronts that pierce the soap bubble. You can see the shadowy mist of the bubble bursting as the flame front expands. Watch the background carefully, and you can see a shock wave flying away from that moment of detonation.

    Once the soap bubble is gone, the expanding flames begin to wrinkle and deform. Turbulence takes shape, eddying through the flames at a much slower speed than the initial detonation. This is where most of combustion takes place, with turbulence mixing the hydrogen and oxygen together to better enable burning. (Image and video credit: L. Gledhill)

  • Sonic Booms and Urban Canyons

    Sonic Booms and Urban Canyons

    In the days of the Concorde — thus far the world’s only supersonic passenger jet — noise complaints from residents kept the aircraft from faster-than-sound travel except over the open ocean. With many pursuing a new generation of civil supersonic aircraft, researchers are looking at how those sonic booms could interact with those of us on the ground.

    In this study, researchers simulated the shock waves from aircraft interacting with single and multiple buildings on the ground. They found that the presence of a building increases the perceived sound level of the boom by about 7 dB at the most. But the most interesting results are what happens between multiple buildings.

    If the street between buildings is wide enough, they each act independently, as if they were single buildings. But for narrower streets, the acoustics waves reflect and diffract between the buildings, creating a resonance that makes the acoustic echoes last longer. The effect is especially pronounced for a sonic boom traveling across a series of buildings, which mimics the layout of a dense city full of urban canyons. (Image credit: Concorde – M. Rochette, simulation – D. Dragna et al.; research credit: D. Dragna et al.)

    Acoustic waves reflect and propagate through 2D urban canyons with widths of 10 meters (top), 20 meters (middle), and 30 meters (bottom).
    Acoustic waves reflect and propagate through 2D urban canyons with widths of 10 meters (top), 20 meters (middle), and 30 meters (bottom).
  • Dripping Impact

    Dripping Impact

    How does water drip, drip, dripping onto stones erode a crater? Water is so much more deformable that it seems impossible for it to wear harder materials away, even over thousands of impacts. To investigate this, a team of researchers developed a new measurement technique: high-speed stress microscopy. In the process, they found that water owes its incredible erosive power to three factors: 1) The drop’s impact creates surface shock waves along the material, which helps increase erosive power; 2) After the shock wave passes, a decompression wave in the material helps loosen surface matter; and 3) The spreading drop sends a non-uniform wave of stress across the material that simultaneously presses and scrubs at the surface. Together, these factors enable simple, repetitive droplet impacts to wear away at hard surfaces. (Image credit: cottonbro; research credit: T. Sun et al.; via Cosmos; submitted by Kam-Yung Soh)