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Old   April 4, 2006, 17:27
Default Hi, To compute flow in rota
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Pei-Ying Hsieh
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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!

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Old   April 4, 2006, 20:45
Default Hi, One more question about
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Pei-Ying Hsieh
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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?

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Old   April 5, 2006, 15:05
Default OK, I found the answer.
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Pei-Ying Hsieh
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OK,

I found the answer.

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

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

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