[Geysers] Conduit dynamics: bottom up or top down?

[Carlton Cross]

Brian,

Good to hear that there are more prizes for model geysers.

I think the answer to your top-down vs bottom-up question will have a great
deal to do with where the heat is applied, where it is lost and how much
convection can occur.  Small models typically have heat applied at the
bottom and loose heat on all other surfaces.  Their small size also
inhibits circulation.  If the surfaces of the reservoir and the exit tubes
were all heated equally, I suspect you would see changes in the behavior.
In one of our larger models--an 8 inch well casing that was 9 feet long
with 5  2 kW heaters about evenly spaced--the eruption definitely started
at the top and dropped downward.

For your two-reservoir system, what would happen if you heated the
connecting tube equally with the bottom surfaces?  I'm guessing that the
cooler water in this tube is what quenches the eruption.  If the tube were
to be hot enough to maintain boiling in the passing water, I bet something
different would happen.

We have almost recovered from winter here, so we may have a few eruptions
coming before long.

Carlton Cross