POV-Ray : Newsgroups : povray.binaries.images : Building types : Re: Building types Server Time
28 Sep 2024 17:52:46 EDT (-0400)
  Re: Building types  
From: Sven Littkowski
Date: 4 Feb 2016 00:57:22
Message: <56b2e842@news.povray.org>
AIR MOVEMENT WITHIN A ROTATING CYLINDER

1
Even air has its mass, and thus also some small amount of inertia.
That's the first thing we need to keep in our mind.

2
The second thing we need to keep in mind, is that air is also flexible,
like all gases.

3
The third thing to consider is, that air gains different weights when
heated up or cooled down.

Prediction
The rotation of the cylinder, especially on its inner surface with all
the buildings and plants, will push the air with it, and thus create a
general air movement towards the same direction as the cylinder rotates.
But because air has its own mass, that movement tends to slow down
towards the inner axis of the cylinder due the own inertia of the air
and its flexibility. On the other hand, the steady and permanent
rotation of the outside air still adds new energy into the air flow,
that is why the rotation will never be zero at the center of the
cylinder. It will just be slower. The surfaces of all the buildings and
plants, even of moving humans and maybe animals, will cause
irregularities in that air movement, those can add to small and
relatively gentle winds under some circumstances, in a cylinder of that
small size (relatively seen). Also, inside that cylinder with light
sources, engines, humans and maybe animals, there will be a generation
of temperatures that are a bit higher than the regular air. Thus, that
warmer and now lighter air will rise towards the center of the cylinder
and thus at the same time causes the cooler and slightly heavier air to
make place and sink downwards, another factor for irregularities in air
movement and generation of gentle winds.

Altogether, I think, inside that cylinder once it has some volume of air
inside, there will be some gentle winds, but probably much below the
speed of 3 km/hour. Along the middle axis (center) of the cylinder, the
air will be much warmer, also towards the light source at the one side
of the cylinder, if I understand that concept correctly. Cooler air from
the sides will move towards the light source, get warmed up (probably),
and moves then along the middle axis. So we talk about two principal air
flows: (A) with the rotation of the cylinder, and (B) from all inner
walls towards the light source end of the cylinder and from there along
the center axis of the cylinder.

This seems to be a guaranty for pleasant, gentle winds. During night
hours, when the light source at the one end of the cylinder is probably
switched off, only the air movement (A) remains. During "day" hours, (A)
and (B) cause air movements.


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