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creepin flow with a new viscosity model

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Old   March 29, 2015, 20:13
Question creepin flow with a new viscosity model
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jafar
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Dear Freeads
i am new in open foam,i want to analysis creeping flow( in steady state case) around cylinder ,i want to use a new viscosity model to calculate apparent viscosity.
how can i add a new viscosity model?
which solver should be used?
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Old   March 30, 2015, 06:16
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Sören Sander
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Hi bagherij,

this should give you a starting point.

Best regards,
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Old   April 3, 2015, 07:46
Talking Thank you
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Dear Sören
thanks,i added new viscosity model ,now i want to calculate shear stress( and compare with yield stress) ,how can i do it?
Best regards
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Old   April 7, 2015, 04:03
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Sören Sander
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The shear stress tensor is calculated by

1. Define a volTensorField named "tau" in your createFields.H

2. Add the following line to your solver
Code:
tau = -mu*(fvc::grad(U)+(fvc::grad(U)).T());
where "mu" is the dynamic viscosity of the system. Depending on your viscosity model, you might have to replace this with your local mu.
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Old   April 14, 2015, 16:14
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Thanking for reply
i added that line to my solver ,when i run below message coming
Error nu was not declared in this scope
mu should be returned by viscosity model .
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Old   April 15, 2015, 11:57
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Sören Sander
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In the tutorial nu is accessed by

Code:
Foam::tmp<Foam::volScalarField>Foam::singlePhaseTransportModel::nu() const
{
    return viscosityModelPtr_->nu();
}
Without knowing your code in detail, i guess you might access your nu the same way.
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Old   July 4, 2015, 21:08
Default calculate shear rate for creeping flow around cylider
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Dear
I add a new viscosity model named "Zhu" to my problem by ,but when i run the code i got some error (in file error( attachment)).i also want to compare shear rate with yeld stressse but i dont know where should i do it.i attach my problem and new viscosity model.please help.
thanks jafar
Attached Files
File Type: gz channelTest6.tar.gz (3.4 KB, 7 views)
File Type: c error.C (3.3 KB, 9 views)
File Type: gz Zhu.tar.gz (58.7 KB, 8 views)
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crepping flow, cylinders, drag force, new viscosity model, openfoam2.3

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