[Geysers] Lone Star Study

[Davis, Brian L.]

Carlton Cross wrote:

> This article perpetuates a major fallacy about geysers.  Eruptions
> are not caused by a buildup of pressure; they're caused by increasing
> temperature and the formation of steam bubbles that reduce the pressure.

Agreed. I've not read the original article as yet (not at school, so harder to get ahold of). Has anyone here? I suspect (I hope!) the original authors didn't make that mistake.

> ...What happens in a constriction is that the pressure drops as the
> fluid moves faster.

I'd not thought of a Bernoulli effect in such geyser constrictions before. You're correct it should happen, but it wouldn't seem to be a factor in initiating such an eruption (prior to the eruption velocities would be very very low). During an eruption the pressure drop due to such flow might be rather small as well... (1/2) rho v^2, for rho = 2-20 [kg/m^3] and v = 20 [m/s], the pressure drop would be around 400-4000 [Pa], or under 0.04 [Atm], equivalent to a change in water level of less than 0.5 [m]. That's not huge (although in some cases could be significant I suppose). And I doubt in-conduit velocities reach too much higher than around 20 [m/s] due to the observed heights of play (24 [m/s] would correspond to a maximum plume height of around 30 [m]). But it's interesting... the dynamic effects are hard to get a handle on, especially with the conduit not being filled with anything like a nice normal fluid during an eruption (very compressible, but with a large effective density relative to normal gases).

Scott Bryan then wrote:

> Seems like in the past few years, a simple study of geyser action is an
> "easy" way to get published!

As I'm one of the Johnny-come-latelys that are riding on the coattails of the rest of you... I'll strongly agree with Scott here while publicly acknowledging I'm one of those. And hope to publish more. I just don't trust my models anymore. I'm starting to eye structures I can build 20 m tall conduits to to get some proper sense of scale... the university is going to love me (or fire me, we'll see which ;) ).

-- 
Brian Davis