Fluid under centrifugal force (Basic)

[alexsb92]

Hi,

What happens to the fluid in a cylinder that is spinned around it's central axis? Would it matter if there would be a bit of air?

Thanks very much,
Alex

 

[CFDFEAGURU]

Depending on how fast you rotate the cylinder, the shape of the surface will approach that of a paraboloid of revolution.

Thanks
Matt

 

[alexsb92]

Hey,

Thanks for the info, but i think i was a bit unclear, as I was meaning that the cylinder is rolling. Forgot that the direction of it will make a difference.

Any ideas about that?

 

[mjcguest]

I don't have the math to back this up, but something's nagging at the back of my head to suggest you're more likely to get a catenary rather than a parabola. I Could be totally wrong on this... Anyone know for sure?

 

[CFDFEAGURU]

Check out "Transport Phenomena" by Bird, Stewart, and Lightfoot.

If the fluid surface is exposed to atmospheric pressure (14.696 psi) then the shape will be a paraboloid of revolution.

Thanks
Matt

 

[mjcguest]

Why the need for atmospheric pressure? A fluid spun in a rotationally will form a parabola in a vacuum, why is this necessary for the rolling cylinder?

 

[CFDFEAGURU]

Yes, a fluid under vacuum will produce the same result. I was just stating the conditions used in the Transport Phenomena book for clarity.

Thanks
Matt