[Venky_94]

Hey,

I'm trying to print out mu and nu values from the simulation for post processing. Along the interface the values are meant to have a linear interpolation, but I'm getting a flat line in all my time steps. Can someone tell me what I'm doing wrong?

What I did was to create an IO object within the createFields.H header as below. I noticed that the mu() and nu() where members of the incompressibleTwoPhaseMixture class and hence I called upon them directly.

// Getting dynamic viscocity for postprocessing
volScalarField mu
(
    IOobject
    (
        "mu",
        runTime.timeName(),
        mesh,
        IOobject::NO_READ,
        IOobject::AUTO_WRITE
    ),
    mixture.mu()
);

// Getting kinematic viscocity for postprocessing
volScalarField nuproc
(
    IOobject
    (
        "nuproc",
        runTime.timeName(),
        mesh,
        IOobject::NO_READ,
        IOobject::AUTO_WRITE
    ),
	mixture.nu()
);

The most possible explanation I could think of is because they're declared as tmp fields in the class, maybe the program isn't able to obtain the values. But I couldn't figure out how to bypass that.
Would declaring them somewhere within the main solver executable (interFoam.C) instead of createFields.H help? Or should they be recalculated within the solver executable?

[Anup Singh]

It has nothing to do with class of IO Object. If you want them to be updated then update them after each iteration.

[Venky_94]

Originally Posted by Anup Singh

It has nothing to do with class of IO Object. If you want them to be updated then update them after each iteration.

And how would I go about doing it? Because of the variables I'm trying to write out, I think mu may not be stored and is calculated every time it is needed but I know for a fact that the solver calculates and *stores* nu every iteration as it is required for consequent equation solving. I'm not sure why it is writing out a constant value every time step.

[Andrea1984]

You want to have a look at interFoam.C. You can see that createFields.H is included once before the start of the pimple loop (this makes sense, given the name of the file!), so all the variables created there are not updated unless you enforce this update at some point within the pimple loop.

In this case, on top of the code that you already have in createFields.H, you might want to include these two lines in interFoam.C right before the end of the pimple loop:

mu = mixture.mu()
nu = mixture.nu()

Hope this helps,
Andrea