[bagherij]

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?

[Sören Sander]

Hi bagherij,

this should give you a starting point.

Best regards,

[bagherij]

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

[Sören Sander]

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

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.

[bagherij]

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 .

[Sören Sander]

In the tutorial nu is accessed by

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.

[bagherij]

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