The power of collapsing bubbles

This cloud of collapsing bubbles are lit up by their own sonoluminescence (2005). Nature

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Cavitation is the term for a phenomenon caused by bubbles collapsing. The idea of bubbles collapsing sounds pretty innocuous, right? But enough of them in the wrong places can cause damage. They can do some valuable work, too. A boat or ship moves because of the bubbles around its whirling propeller. The ultrasonic cleaner in the dentist's office uses cavitation. And the noisy pipes in your house are caused by cavitation. (For example, take a look at this PDF: Why Cavitation Can Destroy Your Pump and Pipes). A small gas bubble, driven at ultrasonic frequencies, can produce sonoluminescence when it collapses. Wikipedia describes how this works.

NASA has an interesting paper titled Development of techniques to investigate sonoluminescence as a source of energy harvesting (2007).

There are some research topics published by Science Daily that may interest you, such as Destructive power of bubbles could lead to new industrial applications (2015). Quoting the article:

Bursting bubbles pull in material like black holes.

Snapping Shrimp Drown Out Sonar With Bubble-Popping Trick (2000):

Until recently, scientists had assumed that the snapping noise occurred when the two parts of the claw banged shut. Now, however, a team of physicists and a biologist have discovered that the noise, in fact, comes from the collapsing of small bubbles generated by the claw's closing motion.

And this showstopper: Temperature Inside Collapsing Bubble Four Times That Of Sun (2005):

“When bubbles in a liquid get compressed, the insides get hot – very hot,” said Ken Suslick, the Marvin T. Schmidt Professor of Chemistry at Illinois and a researcher at the Beckman Institute for Advanced Science and Technology. “Nobody has been able to measure the temperature inside a single collapsing bubble before. The temperature we measured – about 20,000 degrees Kelvin – is four times hotter than the surface of our sun.”

This has lead to the conjecture that nuclear fusion can be generated by cavitation: An Odd Hypothesis About Bubbles Could Finally Lead to Nuclear Fusion (2015).

Possibly cavitation is one of the processes in cold fusion. Don't know. What do you think?

-- Marge