Re: [PSUBS-MAILIST]-pressure test/vacuum

["Jeff Post" <jeffpost@rawbw.com>]

Perhaps has some fluidic properties, but it certainly doesn't exert an equal pressure on a body submerged in the "fluid". This is critical to the test. It is not simply a matter of putting a lot of weight on top of the hull.

 

JP

----- Original Message -----

From: AndrePevestorf@aol.com

To: personal_submersibles@psubs.org

Sent: Saturday, April 13, 2002 4:05 AM

Subject: Re: [PSUBS-MAILIST]-pressure test/vacuum

In einer eMail vom 13.04.2002 05:34:57 (MEZ) - Mitteleurop. Sommerze schreibt jeffpost@rawbw.com:

This absolutely not correct.

It was more a joke.
But seriously if the sub is complete wraped with dry sand (the hole must be bigger the the sub) the dry sand works nearly like a fluid and due to his strong density the pressure on the sub is high.
But you are right of course it would be a stupid idea to do that really...

To evaluate that dry sand can works like a fluid take a bucket pail put a tennis ball on the bottom and fill the pail with fine dry sand.
Nothing will happen.
Now shake the pail with a higher frequenz or put it in your car and drive offroad...
The ball will go to the surface...

Under vibrations geological material like sand works as a fluid (but of course highly non NEWTON´s)

A.