Can Uneven Heating and Mechanical Rotation Generate Winds?

[elusiveshame]

TL;DR

Is it possible to create a closed off wind "box"?

I've had a question bugging me lately and no matter how much I google, I can't seem to find an answer. I'm sure this probably isn't possible, and my logic is probably flawed (Earth sciences isn't my forte), so I figured I'd ask you fine folks here.

First, my understanding of wind, it's caused by uneven heating of the planet + the rotation of the planet.

Would it be possible to make a container that generates its own winds based on uneven heating and mechanical rotation of the closed system? (not that I want to make something like this, just curious if it's even possible)

Sorry if this is a ridiculous question.

Thanks!

 

[jim mcnamara]

Short answer: yes, it exists:
https://web.ornl.gov/sci/buildings/conf-archive/1985 B3 papers/055.pdf

This talks about closed convective loops in buildings. It needs a source of heat and and a heat sink (cold) to work. I'm not sure about the practical uses. The "wind" would not be all that powerful.

I think you want the term: 'closed convective loop' if you google for more information.

@russ_watters knows far more about this I'm sure.

 

[elusiveshame]

Short answer: yes, it exists:
https://web.ornl.gov/sci/buildings/conf-archive/1985 B3 papers/055.pdf

This talks about closed convective loops in buildings. It needs a source of heat and and a heat sink (cold) to work. I'm not sure about the practical uses.

I think you want the term: 'closed convective loop' if you google for more information.

@russ_watters knows far more about this I'm sure.

Oh cool! Yes, the term is exactly what I was looking for. Googling "wind box" or "wind in a box" returns some interesting results, but nothing that helped my question. Thank you!

 

[jrmichler]

No, it's not a ridiculous question. The movement of air in a system, whether planet Earth or a box, is controlled by a combination of forces. Those forces include friction (viscous drag), inertia, gravity, and density. A (not the only) key dimensionless number that summarizes the relationship between these forces is the Grashof number, the ratio of buoyancy to viscous force. Another important number is the Reynolds number, the ratio of inertial to viscous force.

Air movement on a planetary scale is controlled by buoyancy and inertial forces, while air in a box is controlled by viscous forces. Search dimensionless numbers for more information. The Chemical Engineer's Handbook by Perry and Chilton has a few pages on scaling of chemical processes that may be of interest.

 

[Astronuc]

Rather than wind box, the term would be convection box, or convection cell.
https://www.thomassci.com/Equipment-E-through-K-Education-Education-Physics/_/Convection-Box

One could build a tall convection box, and use an electric heater and a cooling coil, or ice block, on the other side.

 

[elusiveshame]

No, it's not a ridiculous question. The movement of air in a system, whether planet Earth or a box, is controlled by a combination of forces. Those forces include friction (viscous drag), inertia, gravity, and density. A (not the only) key dimensionless number that summarizes the relationship between these forces is the Grashof number, the ratio of buoyancy to viscous force. Another important number is the Reynolds number, the ratio of inertial to viscous force.

Air movement on a planetary scale is controlled by buoyancy and inertial forces, while air in a box is controlled by viscous forces. Search dimensionless numbers for more information. The Chemical Engineer's Handbook by Perry and Chilton has a few pages on scaling of chemical processes that may be of interest.

Thanks for the explanation! Are viscous forces the only forces we'd be able to created in a closed system? Would we need basically a planet to create a non-computational model of Earth like winds?

 

[jrmichler]

Would we need basically a planet to create a non-computational model of Earth like winds?

Yes. But if the planet was made of a dense material such as solid gold, and with the right gases in the atmosphere to get comparable Grashof and Reynolds numbers, and closer to the sun for more solar heat, then you could scale it down to less than 1000 miles diameter. Although the ratio of atmosphere depth to planet radius might cause problems with the model.

Have you checked out windy.com? Mesmerizing. And it gives an idea of the complexity of the problem.

 

[elusiveshame]

Yes. But if the planet was made of a dense material such as solid gold, and with the right gases in the atmosphere to get comparable Grashof and Reynolds numbers, and closer to the sun for more solar heat, then you could scale it down to less than 1000 miles diameter. Although the ratio of atmosphere depth to planet radius might cause problems with the model.

Have you checked out windy.com? Mesmerizing. And it gives an idea of the complexity of the problem.

Gotcha. I'll def check out windy.com, thanks!

 

[Keith_McClary]

I'm not sure about the practical uses.

There are convection/gravity furnaces/heaters.