Chris Zell wrote: > It ain't the friction what does it. It's the cavitation.
I realize it's not actually friction. But as regards the expected end result, the difference doesn't matter. Thermodynamically, they're the same thing -- you abuse the substance mechanically, and its molecules end up bouncing around faster. I.e., you squish, rub, pound, twist, stretch, or bounce it, and it gets hot. It's a fundamentally simple situation, and energy-in = energy-out, or so one would certainly expect. Unless the cavitation is causing some (irreversible) chemical or nuclear reaction, it has no more business producing a COP>1.0 than just rubbing two sticks together has. So, the point is, if it's OU, that's big news.
