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The torus-shaped rotating space station, familiar from science fiction, is a way to produce artificial gravity in space. Would the fluid dynamics of gas in a rotating torus cause a person standing inside to notice any airflow?

It's noted (for example Artificial gravity on rotating spaceship?) that inside such a space station the air would rotate with the structure. It's clear that this rotation would be the main motion of the air. however would the variation in centrifugal force or other properties of fluid flow inside a torus cause a secondary motion So that a person standing inside the torus would experience this secondary motion as wind.

Several websites mention fluid flow, for example, Wikipedia notes that fluids can freely move in a vortex. And other sites deal with this https://www.gamedev.net/topic/680801-flying-inside-a-rotating-torus-space-station-artificial-gravity/ mentions "There will be airflow caused by the rotating torus. Laminar flow, oh the joy. That means fastest flow near the floor with quadratic or something falloff". I have also unsuccessfully tried googling for "gas flow inside a torus"

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  • $\begingroup$ Unfortunately, it flushes right out the back. That's how the Federation lost NCC-1700. $\endgroup$ – Ambrose Swasey Feb 1 '17 at 19:30
  • $\begingroup$ Taylor-Couette flow and associated instabilities may interest you. $\endgroup$ – Deep Feb 2 '17 at 4:34
  • $\begingroup$ Vaguely related: physics.stackexchange.com/q/214038/123208 which discusses wind in A. C. Clarke's Rama spacecraft, a large rotating cylinder. $\endgroup$ – PM 2Ring Oct 1 at 5:50
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No, the atmosphere will rotate with the space station, just like Earth's atmosphere.

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    $\begingroup$ Thanks, that is a very short answer, and "just like Earth's" atmosphere raises lots of questions: Earth's atmosphere does have wind, driven by sun. This is more a fluid dynamics question. How does a gas move inside a rotating torus. The motion of air around the rotating sphere doesn't seem to be an good model for the inside of a torus. $\endgroup$ – James K Feb 1 '17 at 19:51
  • $\begingroup$ The answer is, in the frame rotating with the station, the gas doesn't move, unless it is driven by buoyancy gradients. This is, of course, the same situation we have on Earth, mutatis mutandis. Once you have radial motion of fluid, Coriolis forces will affect the motion, causing effects similar to the Trade Winds on Earth. However, these effects will be small on the scale of a space station, and more so if the geometry is that of a "thin" torus. $\endgroup$ – Pirx Feb 1 '17 at 19:54
  • $\begingroup$ Would it be just like Earth's atmosphere? I'm picturing two different situations. One where there is a moving plate below the gas and the other where there is a moving plate above and below the gas. In a small scale, the velocity profiles would definitely be different between the two situations. Is there something that changes when we deal with large scales? $\endgroup$ – JMac Feb 1 '17 at 20:06
  • $\begingroup$ I'm not sure what you mean by those "moving plates", but assuming you are talking about flow in a plane channel, if both plates move at the same constant speed, you can simply transform into a moving coordinate system, in which you have no motion. If the plates are moving at different speeds, you'll get plane Couette flow, with a linear velocity profile for laminar flow, if the Reynolds number $U h/\nu$ (with $U$ velocity difference between the plates, $h$ distance between the plates, $\nu$ kinematic viscosity of the fluid) is less than about 350 or so. $\endgroup$ – Pirx Feb 1 '17 at 20:31
  • $\begingroup$ What you are saying is that solid body rotation results inside the torus. $\endgroup$ – Deep Feb 2 '17 at 4:37

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