In reply to Horace Heffner's message of Tue, 5 Apr 2005 16:46:12 -0800: Hi, [snip] >>Thanks. I have now derived the formula for myself, so I understand >>where it comes from, and what the various constants mean. I have >>also applied the same derivation principle to an active vortex >>that it constantly being "topped up" to maintain a constant level. >>The result for a vortex with no initial angular velocity > >Uh, if there is no initial angular velocity the water merely runs down the >drain. Not sure what you mean here.
What I mean is that the body of water as a whole has no initial angular velocity, though a small portion adjacent to the drain may have. IOW just enough to get the vortex kicked off, so that it can grow from the centre out. Ok, I have now resolved the whole thing. The complete model with freely chosen tank rim parameters (including injection velocity), can now be found at http://users.bigpond.net.au/rvanspaa/vortex-shape+.mcd with gif at http://users.bigpond.net.au/rvanspaa/v-shape.gif Perhaps needless to say, we missed out on that free lunch again! :) Regards, Robin van Spaandonk All SPAM goes in the trash unread.
