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Author Topic: Water and gravity: look at this video  (Read 23349 times)

kajunbee

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Re: Water and gravity: look at this video
« Reply #60 on: December 22, 2022, 02:24:52 PM »

kolbacict

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Re: Water and gravity: look at this video
« Reply #61 on: December 22, 2022, 02:46:43 PM »

Pressure in a sealed vessel is equal throughout the vessel
One cannot sink while the other rises
Can you make a diver so that when the water pressure rises, he floats instead of sinking?

sm0ky2

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Re: Water and gravity: look at this video
« Reply #62 on: December 22, 2022, 03:10:52 PM »
To invert the scenario, implies an inversion of the compression.


Such a bobber would use vacuum-based displacement,
where-in external pressure activates a secondary internal actuator
Increasing the physical volume of the air chamber,


In this bobber the flexible material would be replaced by an expanding rigid chamber
that could support lower internal pressure.
(vacuum-spring?)
The force required to do this would be substantially large.
It may be mechanically possible, but wouldn’t make sense to build such a thing for this purpose




sm0ky2

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Re: Water and gravity: look at this video
« Reply #63 on: December 22, 2022, 03:11:41 PM »
In air buoyancy would be more suitable for vacuum-based buoyant devices

kolbacict

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Re: Water and gravity: look at this video
« Reply #64 on: December 22, 2022, 03:37:06 PM »

The force required to do this would be substantially large.
It may be mechanically possible, but wouldn’t make sense to build such a thing for this purpose
In that case we could to use single aquarium without   partitions.
And the water level would not change from above. :)

sm0ky2

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Re: Water and gravity: look at this video
« Reply #65 on: December 23, 2022, 12:32:24 AM »
Think of it like this:


When you expand a baloon under water:


Such as is done in emergency life jackets, with a CO2 cartridge


You are providing an inner pressure, forcing against the mass of that volume’s
worth of water.


If you sucked all the air out of a military submarine,
while underwater
It would crush like you stepped on an aluminum can.


Your’re fighting the entire atmosphere

sm0ky2

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Re: Water and gravity: look at this video
« Reply #66 on: December 23, 2022, 12:36:23 AM »
The Pistol Shrimp uses this to its’ advantage,
as does a particular high-efficiency water heater


But its not of a lot of use for direct gravitational harvesting
outside of some nano-tech we haven’t invented yet

sm0ky2

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Re: Water and gravity: look at this video
« Reply #67 on: December 23, 2022, 12:39:07 AM »
Its’ called a cavitation-gravitation oscillator
Which uses the difference between 0 ATM and
The 0 state of a denser than air medium
The compress an incalculable mass of incomprehensible atoms
Which in turn radiate all sort of grabbables




Willy

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Re: Water and gravity: look at this video
« Reply #68 on: December 23, 2022, 06:42:50 AM »

In such: the decompression energy from one chamber could add to the compression energy of the other, thereby lowering the energy required to compress the air.
The equilibrium state would be approx half-compression in both.
The piston would only have to half-compress either chamber while energy is extracted from both.
Hmm ;)


                             Very cool

sm0ky2

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Re: Water and gravity: look at this video
« Reply #69 on: December 23, 2022, 05:20:55 PM »
In most cases, the height of the water tank is not large enough to make a
substantial change in the pressure of the bobber


When pressure inside the tank is returned to its’ rest state,
the air inside the bobber is more than capable of re-expanding itself

sm0ky2

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Re: Water and gravity: look at this video
« Reply #70 on: December 23, 2022, 05:25:52 PM »
Real-world example:


Sink a raft in the ocean


You will need to go down several hundred feet before it
irretrievably collapses under the pressure of the ocean.
Fresh water is less dense so it would take an even greater depth


YES there is a change in pressure by depth
And we can calculate exactly how much this changes.


Doesnt affect the action of the Cartesian Diver until very great
heights are reached within the water column.


The ranges we would use for any sort of application,
fall well within normal operating conditions

MT

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Re: Water and gravity: look at this video
« Reply #71 on: December 27, 2022, 12:52:21 PM »
YES there is a change in pressure by depth
And we can calculate exactly how much this changes.

Doesnt affect the action of the Cartesian Diver until very great
heights are reached within the water column.

The ranges we would use for any sort of application,
fall well within normal operating conditions

Was searching a bit diving websites and yes it should not have much impact for devices with practical dimensions like 1-2 meters of height. According to Boyle's law, doubling pressure halves gas volume at constant temp. And pressure at water increases slowly, 1/10th of bar per meter.
 
So a diver starting at surface with ~1bar pressure and 4liters of ideal gas volume would need to go 10meters deep to see its volume halved. At 30meters it would be just 1 liter.

That shrinking works in our advantage when diver is sinking as volume is lower and is thus even less buoyant and similarly during rising it works in our disadvantage.

MT

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Re: Water and gravity: look at this video
« Reply #72 on: December 27, 2022, 01:09:35 PM »
Question, have you or maybe somebody else already did some or even complete energy calculations of this design on a concrete example?


I mean first initial energy of whole system with diver at top. Then:
1. energy needed to compress
2. work bober can produce on its way down
3. energy that can be retrieved during decompression of whole system with diver down
4. work bober can do on its way up.


For example 1m3 aquarium, 10kg diver with 12 liter of ideal gas.

sm0ky2

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Re: Water and gravity: look at this video
« Reply #73 on: December 27, 2022, 05:19:39 PM »
I have not made any sort of prototype




sm0ky2

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Re: Water and gravity: look at this video
« Reply #74 on: December 27, 2022, 05:30:10 PM »
Here is the basic physics.
Displacement of the motive mechanics will need to be accounted for


https://physics.anu.edu.au/engage/outreach/_files/Cartesian%20Divers.pdf


Here is a more in-depth analysis
Which shows irreversible sinking as a factor of bobber diameter.


https://iypt.ru/wp-content/uploads/2020/10/A-lot-of-good-physics-in-the-Cartesian-diver.pdf