[rasool_soofi]

Hi everyone!

As you know OpenFOAM announced a new function object for solving scalar transport in only one phase of multi-phase flow solvers especially interFoam. (https://twitter.com/cfddirect/status...167872?lang=en)
I believe here is the best place to discuss about phaseScalarTransport features, advantages and limitations. when OpenFOAM applies this part of code to the algorithm, basically solute (e.g. s.water) diffuses into the second phase but this algorithm will multiply it to the alpha.water (volume fraction in interFoam solver) and then solve the next time step.

fvScalarMatrix fieldEqn
              (
                  fvm::ddt(alpha, s_)
                + fvm::div(alphaPhi, s_, divScheme)
                - fvm::laplacian
                  (
                      fvc::interpolate(alpha)*fvc::interpolate(D),
                      s_,
                      laplacianScheme
                  )
               ==
                  fvOptions_(alpha, s_)
                - fvm::ddt(residualAlpha_, s_)
                + fvc::ddt(residualAlpha_, s_)
                );

the first question is that how can we explain the physical boundary condition of s.water over the interface? (regrading to the code)

and when I tried a simple test case: (interFoam + phaseTransportFoam)

initial conditions of alpha.water and s.water: (link below)
https://drive.google.com/file/d/1Jth...ew?usp=sharing
indeed when solute spreads to the blue phase it propagates and gives artificial diffusion https://drive.google.com/file/d/1ja9...ew?usp=sharing

so the second question is:
how can we prevent s.water to diffuse to the blue phase causing this artificial diffusion. (maybe related to the first question)

actually with multiplying s.water to alpha it reduces the whole initial amount of solute in the main phase.


any explanation or help would be highly appreciated!
Rasoul

[randolph]

Rasoul,

I think I have the answer to your questions in this post.

interFoam with scalar transport in single phase

Thanks,
Rdf

[Sud_fluid]

Hi,


I'm also trying to simulate a case (similar to sand in water + air) however I do not understand how to implement the phaseTransportFoam (in particular could you please explain what you meant by interfoam + phaseTransportFoam).

I tried to implement this in the dambreak case. In the controlDict, file I included the following lines before the end.

phaseScalarTransport1
{
type phaseScalarTransport;
libs ("libsolverFunctionObjects.so");
field s.water;
p p_rgh;
}

phaseScalarTransport2
{
type phaseScalarTransport;
libs ("libsolverFunctionObjects.so");
field alpha.water * s.water;
p p_rgh;
}
Then I run the command "interfoam" which ends well but when I enter the command "phaseTransportFoam" it is not found. Could you please tell the steps clearly on how to implement phaseTransportFoam.


Thanks.
Sudarshan.

Originally Posted by rasool_soofi

Hi everyone!

As you know OpenFOAM announced a new function object for solving scalar transport in only one phase of multi-phase flow solvers especially interFoam. (https://twitter.com/cfddirect/status...167872?lang=en)
I believe here is the best place to discuss about phaseScalarTransport features, advantages and limitations. when OpenFOAM applies this part of code to the algorithm, basically solute (e.g. s.water) diffuses into the second phase but this algorithm will multiply it to the alpha.water (volume fraction in interFoam solver) and then solve the next time step.

fvScalarMatrix fieldEqn
              (
                  fvm::ddt(alpha, s_)
                + fvm::div(alphaPhi, s_, divScheme)
                - fvm::laplacian
                  (
                      fvc::interpolate(alpha)*fvc::interpolate(D),
                      s_,
                      laplacianScheme
                  )
               ==
                  fvOptions_(alpha, s_)
                - fvm::ddt(residualAlpha_, s_)
                + fvc::ddt(residualAlpha_, s_)
                );

the first question is that how can we explain the physical boundary condition of s.water over the interface? (regrading to the code)

and when I tried a simple test case: (interFoam + phaseTransportFoam)

initial conditions of alpha.water and s.water: (link below)
https://drive.google.com/file/d/1Jth...ew?usp=sharing
indeed when solute spreads to the blue phase it propagates and gives artificial diffusion https://drive.google.com/file/d/1ja9...ew?usp=sharing

so the second question is:
how can we prevent s.water to diffuse to the blue phase causing this artificial diffusion. (maybe related to the first question)

actually with multiplying s.water to alpha it reduces the whole initial amount of solute in the main phase.


any explanation or help would be highly appreciated!
Rasoul