What happens when cavitation bubbles collapse in liquid metal coolants?
This study combines simulations and ultrasonic experiments to link bubble collapse dynamics with surface damage in lead-bismuth eutectic used for advanced nuclear reactors.
🔗 https://pubs.aip.org/aip/pof/article/38/4/042006/3386755/Temperature-driven-cavitation-lead-bismuth
#Cavitation #FluidDynamics #NuclearEngineering #LiquidMetals #MaterialsScience
When two cavitation bubbles form near a particle in sequence, their collapse is no longer independent. The second bubble reshapes the jet from the first, creating regimes of deflection, amplification or damping depending on timing.
Sonoluminescence: Light from Collapsing Bubbles
Definition
Sonoluminescence is the emission of short flashes of light when gas bubbles in a liquid rapidly collapse under the influence of an acoustic (ultrasonic) field.
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Physical Mechanism
The process is driven by an oscillating pressure field:
1. Acoustic forcing: An ultrasonic wave creates alternating rarefaction and compression phases in the liquid.
2. Bubble nucleation and growth: During rarefaction, microbubbles form and expand.
3. Violent collapse: In the compression phase, the bubbles implode symmetrically.
4. Extreme conditions: At collapse, the bubble interior reaches:
Temperatures on the order of 10⁴ K
Pressures of hundreds of atmospheres
5. Light emission: A sub-nanosecond flash is produced.
This behavior is a manifestation of Cavitation under controlled acoustic excitation.
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Emission Mechanisms (Competing Models)
Thermal (blackbody-like) radiation from a highly compressed, heated gas core
Plasma formation with ionization and radiative recombination
Bremsstrahlung due to rapid deceleration of charged particles
No single model fully explains all observed spectra and timing; current consensus suggests a combination of these effects.
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Regimes
Single-Bubble Sonoluminescence (SBSL): A stable, trapped bubble emitting periodic flashes synchronized with the driving frequency
Multi-Bubble Sonoluminescence (MBSL): A cloud of bubbles producing spatially distributed, less coherent emission
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Experimental Signatures
Point-like, blue-white flashes in a dark liquid
Strict synchronization with the acoustic cycle
Sensitivity to dissolved gas type, liquid purity, and acoustic amplitude
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Significance
Sonoluminescence provides a laboratory-scale platform to study:
Extreme thermodynamic states in microscale volumes
Nonlinear acoustics and bubble dynamics
Energy focusing and potential plasma formation in liquids
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Conclusion
Sonoluminescence is a robust, experimentally verified phenomenon where acoustic energy is concentrated into a microscopic volume, producing light via extreme compression of a gas bubble.
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#Sonoluminescence #Cavitation #UltrasoundPhysics #BubbleDynamics #NonlinearAcoustics #PlasmaPhysics #FluidDynamics #ExtremeConditions #AcousticEnergy #PhysicsExperiments #LightEmission #ScientificPhenomena
https://bastyon.com/svalmon37?ref=PJ51iZCUEtcVrCj4Wof8Am7FbKLgbAJ7PS
When two cavitation bubbles of different sizes collapse, they form distinct jet patterns that affect local pressure and energy distribution.
Understanding these dynamics helps predict damage in hydraulic systems.
🔗 https://doi.org/10.1063/5.0319732
#cavitation #bubbledynamics #fluidmechanics #EnergyTransfer #hydraulics
Energy redistribution between bubbles depends on initial size and pressure.
Understanding these mechanisms helps improve models of bubble clouds in fluids, relevant from naval to biomedical applications.
🔗 https://doi.org/10.1063/5.0300783
#bubblyliquids #fluiddynamics #bubbledynamics #EnergyTransfer #cavitation
Observation de l'écoulement d'un fluide autour d'une section cylindrique
Animation: Synchronisationsschema EuXFEL-Messzeit p2207
“Broken Water, Like Broken Glass”
How can you break water? By accelerating it so quickly that the pressure drop forms cavitation bubbles. Here, a steel piston rests against a transparent plate, all underwater. When a hammer strike accelerates the piston away at around 1000g, the severe pressure drop tears the water into bubbles (bottom, left). As the bubbles expand, the nearby piston squishes them into pancakes (bottom, center). As they continue growing, the bubbles press into one another, squeezing thin ridges of water between them. The result (center) resembles broken glass. (Image credit: J. da Silva et al.)
#2025gofm #cavitation #flowVisualization #fluidDynamics #physics #science
Aus dem Archiv:
Ein roter Laserpuls hat in Wasser eine explodierende Plasmablase gezündet.
Von links erfasst ein hochbrillanter Röntgen-Freie-Elektronen-Laserblitz die Szene holografisch.
Ein Mikrofon zeichnet akustische Signale auf.
An der Wand sehen wir die entstehenden Blasen zu verschiedenen Zeitpunkten.
(nächster Trot: Link zum Video)
What Limits a Siphon
Siphons are a bit mind-boggling for anyone who has internalized the idea that water always flows downhill. But gravity actually allows a siphon’s water to flow up and over an obstacle, provided certain conditions are met. Steve Mould digs into the details of those conditions in this video, where he searches for the maximum height a siphon can reach.
A quick note on terminology: Steve explains that the siphon breaks when water near the top starts “boiling.” Other sources may use the term “cavitating” for this sudden phase change. There’s not–to my knowledge–a generally-agreed-upon definition that clearly distinguishes between boiling and cavitation in this situation. Whichever term you use, the water in the siphon doesn’t care; either way, it’s experiencing a local pressure that’s so low that it switches from a liquid state (where it can resist tensile forces) to a gaseous one (where it cannot resist tension). (Video and image credit: S. Mould)
#cavitation #DIYFluids #fluidDynamics #physics #science #siphon
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