[PSUBS-MAILIST] air flow vs. water flow

[Antoine Delafargue via Personal_Submersibles]

Hi Alec
What a creative idea!
Viscosity of air being around 0.02cp vs 1cp for water, you d have it 50
times faster with air assuming laminar flow.
I d bet it id Probably a bit less than 50x in reality given the (moderate
?) turbulence.
You could use that to get a rough idea of the reynolds number?

Regards
Antoine

On Thursday, Match 29, 2018, Alec Smyth via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Hi everyone,
>
> I was testing one of my new MBTs yesterday, removed from the sub, by
> turning it upside down and filling it with water, then opening the mushroom
> valve to let the water out. It takes 60 seconds to empty. In actual
> operation it will be air instead of water coming out that valve. The
> pressure will be the same, but because it will be air instead of water the
> tank should empty much faster. The question is, does anyone know more or
> less *how much* faster? One should be able to calculate this with
> Bernoulli's formula, but this is very turbulent flow so not sure if it
> would really hold. Any rules of thumb?
>
>
> Thanks,
> Alec
>
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