[Mirage]

Dear Foamers,

I m writing the heat flux as output only for the last time step and I would like to average this latter parameter over the time using the fieldAverage function.
It works fine for standard variable like p or U. I am getting UMean and pMean as an output and the values are physical after averaging over a long time.

However I am not able to average any new variable, that I m calculating in my customized solver.
Here is the function, that I writing in controlDict:

 fieldAverage1
    {
        type            fieldAverage;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled         true;
        outputControl   outputTime;

        fields
        (

            TurbFlux 
            {
                mean        on;
                prime2Mean  on;
                base        time;
            }
}

Is it possible to average non-standard variable?
I am wondering, what i am doing wrong.

I appreciate any help !

Cheers !

[Mirage]

Should I define the new variable in the OpenFoam libraries ?

Any help or answer is appreciated

[agustinvo]

Hello

I passed through this two weeks ago. First of all, if you can include that variable in your code, that's is the easiest, but if you define Turbflux for example as a Swak4Foam field in yout controlDict, please take a look to this:

https://www.cfd-online.com/Forums/openfoam-programming-development/142749-using-fieldaverage-together-swak4foam-expressionfield.html#post622399

BTW, are you trying to get the turbulent heat flux from your simulations?

[Mirage]

Thanks !!

I managed to calculate the turb flux using the expressionfield of swak4foam tool.


However I am really interested on calculating the average variable in the code.

I could define the flux as variable in the solver. Nevertheless I was not able to average it.
fieldaverage function is not allowing the averaging of non-standard OF variables.

Do you know, if I could define the time averaging on the solver?

[agustinvo]

Hi,

you may take a look into the code of fieldAverage. Me, I've never tried to do so.

What I do is, in my solver, define some auxiliar variables, that I use later to create my turbulent heat flux.

The THF is defined as <u'T'>, but it can be decomposed, follogind the ensemble averaging, as <u'T'>=<UT> - <U> <T>, so you need to create a variable UT, you get the mean of UT, U and T, and then with expressionField you get u'T'.

This is what I do, but fi you find any other easier way to get it, make us know!

[hakolekar]

Hi,

Is it possible to find the field average (over a certain time interval) of volScalarFields in the defined in the member functions of OpenFoam - without using the swak4foam?

For example - the production term in the k equation.

I have already defined this as an IO object and have a data set for this term in my time directories, but it does not produce field averages and instead states:
Field Pkt not found in database for averaging

If anyone has any ideas, it would be appreciated.

Regards,
Harshal

[kkpal]

Hi Harshal,
Have you found a solution to this?

Originally Posted by hakolekar

Hi,

Is it possible to find the field average (over a certain time interval) of volScalarFields in the defined in the member functions of OpenFoam - without using the swak4foam?

For example - the production term in the k equation.

I have already defined this as an IO object and have a data set for this term in my time directories, but it does not produce field averages and instead states:
Field Pkt not found in database for averaging

If anyone has any ideas, it would be appreciated.

Regards,
Harshal