How does one calculate the velocity and strengh of a whirlpool?

[Niaboc67]

For example the earthquake in Japan awhile back had the strength to capture a boat within it's pull. Yet the whirlpool created when someone pulls a plug on the bathtub is hardly any pull whatsoever. This may be a simplistic way of putting it, and i know it has to do with the amount of water and current. How would something like this be put into a mathematical equation too.

Thanks

 

[davenn]

For example the earthquake in Japan awhile back had the strength to capture a boat within it's pull. Yet the whirlpool created when someone pulls a plug on the bathtub is hardly any pull whatsoever.
Thanks

thats purely a question of scale. The small whirlpool in a plughole in the tub will still pull in objects of a relative smaller size

Dave

 

[Bobbywhy]

Niaboc67,

Here are three Wiki pages that give lots of information about whirlpools. See:

http://en.wikipedia.org/wiki/Vortex
http://en.wikipedia.org/wiki/Whirlpool
http://en.wikipedia.org/wiki/Maelstrom

Cheers, Bobbywhy