It's quite easy... Most high power SONAR systems can do it. Cavitation was always a concern of the higher power SONAR heads. Things that could do 230-235 dB at 38 to 50 kHz. Even higher, further up in frequency. And could be done with just 300-500W of power.
Look for info on SONAR head design. However, if you're looking to do it for energy generation via release of hydrogen, it's terribly inefficient. It'll take A few hundred Watts to get a few Watts of hydrogen.
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They can explode human and everything that contains water in a molecular particles. Resonance of water and Tesla's invention are most powerful weapon today. Atom bomb is a toy now. Please share!
It's 42 kHz which can be be achieved by either ultrasound or radiowaves or both but because you need pure water to split it at this frequency so it's kinda impractical - tho if you vibrate water at this frequency it makes standard electrolosys more efficient - several designs to do this exist in the literature
Here is the most sound conclusion:
"In classical acoustics, a medium (such as water) does not have a resonant frequency. Instead, resonance is determined by the dimensions of the boundaries, such as the length of an organ pipe. If there are no boundaries, there is no resonance.
One will have to go to molecular acoustics in order to find resonance in the media itself. I am not terribly good at these things, but I do know that these things occur at very high frequencies. We are talking gigahertz here. I think this is not the way to go for a hobbyist.
Instead, I would go for a resonator of some kind.
You would also have to read up on the references for sound pressure (dB) that are used. 180 dB under water is not the same as 180 dB in air."
Here's the discussion. These guys know their stuff and you will be able to understand what you are saying, and get smarter too!
rats... I was so totally going to say 2.4GHz...