what causes cavitation?

what causes cavitation and what is its remedy?

Not flossing regularly.

You talking about with pumps? It can cause premature failure of a pump.
A liquid when it is subjected to a low pressure ruptures and forms vaporous cavities.

Here is something,
http://engineering.wikia.com/wiki/Cavitation

In my former life, cavitation was a big issue. If you turn the propellor of a submarine too fast, air bubbles form off the tips of the blades. This is a noise which can be heard. Not good. The solutions are..extreme precision machined blades, and observe the depth/rpm curves. The deeper you are, the faster you can go without cavitating.

These days, they have come up with caterpillar drives, or some such, so it is less of a problem. Those suckers go a bunch faster than we did, but to help on total weight, their hulls are not quite the same so they do not go as deep. Now that Virginia class they are building today...those suckers do it all!

In pumps, cavitation occurs when the pump is able to pull vacuum sufficient to liberate oxygen from water. In water pumps it can become an issue because the air bubbles will re-form on the discharge side of the pump and if not eliminated will eventually air-lock the pump. Same for a heating system. The buildup of air will eventually cause the circulating pump to not be able to move water. Does cavitation effect the longevity of the pump? Depends on whether the liquid is also the pumps lubricant. A cavitating pump will actually draw less amps than one that is moving full volume.

cavitation

Cavitation is caused whenever the flow of water to a pump is less than optimal so a negative pressure occurs. This causes the equivalent of "steam" bubbles in the water and when they condense back to water they do so with "mini" explosions which will pit and wear the impeller device. This is one reason you should NEVER install a control valve on the line INTO any pump, even a recirculation pump, but rather on the outlet.

hj said:

Cavitation is caused whenever the flow of water to a pump is less than optimal so a negative pressure occurs. This causes the equivalent of "steam" bubbles in the water and when they condense back to water they do so with "mini" explosions which will pit and wear the impeller device. This is one reason you should NEVER install a control valve on the line INTO any pump, even a recirculation pump, but rather on the outlet.

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Know where I see this all the time? Camps with shallow well pumps. They install a globe valve, cause they are cheap, on the pump inlet for reasons known only to them. Naturally, globe valves restrict, causing cavitation, causing excess air in the tank or system.