[Simbelmynë]

Hi,


I would like to modify a function object that solves some scalar transport, let's say for T.


I use the multiphaseEulerFoam as basis for this and if I try to access the T field in multiphaseEulerFoam.C it is not declared. If I declare it in createFields.H then I can access it, however, then it seems that the function object becomes dormant (i.e. there is no transport of T).


Is there any way around this or do I have to ignore the function object and implement the transport equations for T explicitly?

[mAlletto]

I did not exactly understand what you want to do but there is a scalarTransport function object OF


https://www.openfoam.com/documentati...transport.html

[Simbelmynë]

Thank you for your reply. So if we use your link as example then perhaps I can explain better.


In the example we have a field called "vapour". I assume that we add this information to the controlDict, so there is no compilation of a custom solver involved.



I wish to perform a modification to the vapor field during the solution process. Let's say I just wish to change the value:

forAll(vapour, i)
{
     vapour[i] += 1.;  // The real value is dependant on other field variables such as density and temperature.



}

I have tried to do this modification in the custom solver, and in doing so I add vapour to createFields.H. This seems to override the function object in controlDict and it does not solve for transport any more.



So basically: I wish to use (if possible) a function object and I wish to modify the function object from a custom solver.

[mAlletto]

There are coded function objects. Is this from help?

If there are two fields with the same name one may beoverridden. The fields are stored via a hash table in the database. The key is the name of the field

[Simbelmynë]

Yes, this seems reasonable.


Any suggestion on how to access and modify a variable (e.g. "vapour") from within the solver? Is it possible or should I just define the scalar transport equations in the solver and ignore to use the scalar transport function object?

[mAlletto]

volScalarField& vapor =
const_cast<volScalarField&>
(
mesh().lookupObject<volScalarField>("vapor")
)

Lookupobject gives you a constant reference and you have to cast it to modify it