Re: [PSUBS-MAILIST] Bubble question Psubs disscussion

["Herve" <caribsub@coqui.net>]

Yes John, bravo ! , how accurate, yes the bubble would be a very thin
horizontal shape disk, regardless of th esize.
your description is exact.
and under hydrodynamic effect, the disk becomes a fat lenticular shaped
Herve
----- Original Message -----
From: "John R. Farrington" <jrf@austin.ibm.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, January 28, 2003 6:01 PM
Subject: Re: [PSUBS-MAILIST] Bubble question Psubs disscussion


>
>
> > Actually , i have a question for those interested in physics under the
water
> > and mind games.
> > he he lets see who guess it right here, Jeffrey you are welcome........
> > what would be the shape of an air bubble in the water without the
> > hydrodynamic effect (which deforms the bubble because of water flow)
> > imagine an air bubble trapped in a container of water, itself going to
the
> > surface at the speed ascent of an  air bubble. so the only forces
exerted on
> > the bubble are the water pressure.   water around the bubble is moving
with
> > the bubble, so there is no flow around the bubble, the container takes
the
> > hydrodynamic forces.
> > Herve
>
>
> If the bubble is not constrained in any way (like in a balloon), and that
> no hydrodynamic forces exist in this theoretical model, I'd think that the
> bubble would have to take on an infinitely thin shape of a plane,  (not
> an airplane, a geometric plane), with all points at the same depth.  If
any
> point in the bubble was deeper than another, the pressure on that point
would
> be greater than anywhere else in the bubble and would be pushed into the
bubble.
> (The pressure in a gas is uniform - so all points in the bubble must be at
> the same pressure (depth)).
>
> So, would it take on the shape of a very thin sheet rising to the surface?
>
>
> -John
>
> ps.  Interesting how bubbles of different size take on different shapes.
Real
>      small ones stay nearly perfectly round (cohesion?), while larger ones
>      can take on the shape of a mushroom cap or the shape of a jellyfish.
Others
>      are like inverted raindrops.
>
>
>