fvSchemes in bubbleFoam
 

I was trying to modify bubbleFoam before going to more complex problems.
When I looked at "fvSchmes" located in the systmes foler of bubbleFoam,
I was not sure about it. Here are two questions.

Q1. I think I have to consider below shemes for Rca and Rcb, respectively, but why are they not included in the schemes?

...
div(phiRa, Ua) Gauss limitedLinearV 1; //why is it not included?
div(phiRb, Ub) Gauss limitedLinearV 1; //why is it not included?
...
div(phir, alpha) Gauss limitedLinear01 1; //Need for alpha continuity equation?
...

Q2. I think I could use div(Rca) and div(Rcb), but it could not work. The solver looked for div(-nuEffa*grad(Ua).T()) and div(-nuEffb*grad(Ub).T()).

In UEqns.H,

volTensorField Rca = -nuEffa*(fvc::grad(Ua)().T());
Rca = Rca + ...;


I would really appreciate that if you could give some commenst to me.

The piece of code in the equation says:

so the scheme specified for div(phia,Ua) is used for this term too.

The code for the alphaEqn contains

where

So, it is sufficient to specify a scheme for div(phi,alpha). This is done for consistency of the discretisation.

If you look at the tutorial case, these schemes are specified:

However, in general, if you define a field, its string name is used to look up in the dictionaries, and not its variable name. For example, if you define

the code won't look for "a", but for an expression derived from the calculation. If you want to fix this problem, simply assign a name to your field:

and the code will look for "a" in the dictionaries, instead than for the, usually complicated, expression.

Best,