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July 3, 2012, 09:23 
interFoam with centrifugal Force

#1  
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Matthias P
Join Date: May 2010
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Dear Foamers,i try to simulate the development of a liquid parabola in a cylinder which is filled with water by one third. The other part is captured with air. For regarding the rotation of the fluid i included the centrifugal force in the solver interFoam like it is shown below.
Quote:


January 24, 2013, 06:11 

#2 
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Hello MatP,
I think the formula in your Ueqn() is wrong. Why did you add rad_ ? How did you define rad_ and omega_? Last edited by styleworker; January 24, 2013 at 11:13. 

January 24, 2013, 12:30 

#3 
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Actually I just have a little difference between MRFInterFoam and interFoam including centrifugal force for steady state and moderate angular velocities.
Modified UEqn: Code:
fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U)  fvm::laplacian(muEff, U)  (fvc::grad(U) & fvc::grad(muEff)) //+ Fcent + (rho*((2.0*M_PI/60.0*omega_vector)^((2.0*M_PI/60.0*omega_vector)^mesh.C()))) //omega_vector[1/s] in [rad/m] // fvc::div(muEff*(fvc::interpolate(dev(fvc::grad(U))) & mesh.Sf())) ); Code:
dimensionedVector omega_vector(twoPhaseProperties.lookup("omega_vector")); Code:
omega_vector omega_vector [ 0 0 1 0 0 0 0 ] (0 0 5); 

March 30, 2013, 14:14 

#4 
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Eric Dalmau
Join Date: Mar 2013
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Thanks a lot for your info styleworker, it was so helpful for my case. I had to add the centrifugal force to MRFInterFoam.


March 13, 2014, 22:39 

#5  
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Huang Xianbei
Join Date: Sep 2013
Location: CAU,China
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Quote:
I tried your method, but the code can't be successfully compiled. Code:
omega^(omega^mesh.C()) Code:
omega omega [ 0 0 1 0 0 0 0 ] ( 0 0 0.01335 ); Code:
dimensionedVector omega ( transportProperties.lookup("omega") ); 

March 14, 2014, 03:54 

#6 
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Without any error message, we can't give you an advice.
If you have just inserted this peace of code in your equation, your dimensions probably don't match. The dimension of the in the UEqn should be [kg/m^2s^2], because it is a volume force [N/m^3]. Your volume force should be implemented like this: Code:
fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U)  fvm::laplacian(muEff, U)  (fvc::grad(U) & fvc::grad(muEff)) + (rho*(omega ^ (omega ^ mesh.C()))) //Centrifugal Acceleration ); 

March 14, 2014, 07:48 

#7  
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Huang Xianbei
Join Date: Sep 2013
Location: CAU,China
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Quote:
Thank you, but my UEqn is without rho, just looks like fvm::ddt(U), so this is no the exact reason. I have solved this problem by identify the centrifugal force as a vector field, so this works well. 

March 25, 2015, 12:16 

#8 
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I've got a private message concerning this topic. In more recent releases of interFoam transportProperties isn't initiated explicitly in createFields.H.
Therefore this code snippet has to be implemented before dimensionedVector omega is set: Code:
IOdictionary transportProperties ( IOobject ( "transportProperties", runTime.constant(), mesh, IOobject::MUST_READ, IOobject::NO_WRITE ) ); 

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