CFD Online Discussion Forums - alpha fields in multiphase tutorial cases

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alpha fields in multiphase tutorial cases

hi,

I have looked up now several multiphase tutorial cases and within the 0 folders are some kind of phase fraction fields (alpha) already stored (E.g. tutorial case bubbleColumn of multiphaseEulerFoam.)

My questions are...

1. How can the fields (internal fields) have been described without running "blockMesh" before and therefore not knowing the mesh-structure and cell-numbers?

2. If this is some kind of special procedure - how does it work and where are the fields read and stored in multiphaseEulerFoam?

Edit:

3. Most importantly: Can I access the phasefraction fields of each phase by doing

Code:

PtrDictionary<phaseModel>& PhasesPtrDictionary = fluid.phases();

wordList Phasenames 

(

    PhasesPtrDictionary.toc()

); 

for (int currentLoopPass = 0; currentLoopPass <= 5; currentLoopPass++ )

{

word actualPhase = Phasenames[currentLoopPass];

phaseModel* ActualPhase = PhasesPtrDictionary.lookupPtr(actualPhase);

volScalarField& AlphaActualPhase = *ActualPhase;

}

?

greetings
maybee

Accessing values of a phase in a certain cell zone

Hi,
In regard to your 3rd question:
You can definitely access the zone volumes. In fact it is automatically displayed onto your log during run time. The only pre- requisite is that, you need to have defined cell zones in your mesh.

You can define it in your blockMeshDict when you define your block. You can verify the existence of your zones in the poly mesh directory after running blockMesh.

Another hint for tracking cell zone based values would be through the use of libsofunctionobjects in controlDict, again a cell zone must be defined while creating the mesh.

Hope this helps.

Regards,
Chethan

Quote:

You can definitely access the zone volumes. In fact it is automatically displayed onto your log during run time. The only pre- requisite is that, you need to have defined cell zones in your mesh.

Actually I did not want to access the zone volumes, but the phase fractions of each phase. Will my code work?