system
Given the following post, respond as if you're commenting on Reddit:
human
Is there a theoretical maximum for how fast a propeller can turn in water, yet still be effective?

If a propeller were rotating under water, at some point would the RPM be so great that it moves more quickly than the water can fill the "gap" behind it?

Or perhaps, is there some kind of theoretical upper limit as to how much force can be generated from the RPM of the propeller?

Or, is there some speed at which the kinetic energy produced by the propeller boils the water, possibly causing any loss of effectiveness? (if that's even possible).

I would be really interested in learning about the fluid dynamics that are going on here.
gpt
Cavitation is caused when the propeller (or impeller) moving through water (in this case) causes the water pressure to fall lower than the vapor pressure of its dissolved gases, resulting in a cavity of gas forming around the propeller. When the prop/impeller slows and water pressure climbs, the gases are then able to absorb into the water again and "collapse" with force against the prop/impeller, thereby causing a small implosion and causing stress to the prop/impeller. As such, greater depth of water, which is at a higher ambient pressure and therefore its vapor pressure is higher, results in a greater ability to increase prop/impeller speed without resulting in cavitation.