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-   -   Rotating reference frame (http://www.cfd-online.com/Forums/openfoam-solving/60263-rotating-reference-frame.html)

hsieh April 4, 2006 17:27

Hi, To compute flow in rota
 
Hi,

To compute flow in rotating reference frame, centrifugal force and coriolis force are added to the momentum equation. If omega (rotation speed) is constant, then, one will compute these forces like the following:

dimensionedVector Omega
(
"Omega",
dimensionSet(0,0,-1,0,0),
vector(0, 2 *PI/60 *RPM, 0)
);
//centrifugal foce
volVectorField Fcent = (Omega ^ (Omega^mesh.C()));
// coriolis force
2*Omega ^ U)

What will happen if Omega varies with time? Is there any extra terms needed to be included?

Thanks!

Pei

hsieh April 4, 2006 20:45

Hi, One more question about
 
Hi,

One more question about this.

If the computational domain locates R away from the axis of rotation, where R >> l (l is the characteristic length of the computational domain), how does it affect the centrifugal force/coriolis force calculation?

Pei

hsieh April 5, 2006 15:05

OK, I found the answer.
 
OK,

I found the answer.

Another force term due to angular acceleration needs to be added as follows:

d(Omega)/dt ^ mesh.C()

pei


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