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concerning the fvOptions of explicitPorositySource

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Old   January 28, 2019, 00:30
Question concerning the fvOptions of explicitPorositySource
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Hi, everyone here, I have some questions about the default fvOptions of explicitPorositySource.

What I was trying to solve was a tube reactor filled with catalyst,
so I applied a explicitPorositySource to simulate the DarcyForchheimer law.
The result seems very good and no problem.
But when I reading the code, I was confused.

I found a reference called "Porous Media in OpenFOAM" written by Haukur Elvar Hafsteinsson.
In the file, he gave the momentum equation like


in which the Si represents the porous resistance calculated by explicitPorositySource,
and there is a porosity(Gamma) appearing in the time derivative term.

However, the code of the solver is like

in which the time derivative term do not contain the porosity.

So, does anyone know why is this?
Does this mean that if I want to simulate a porous media, I just set the explicitPorositySource,
and do not need to modify the time derivative term in other equations such as the mass and species and energy equations?

Thanks
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Old   July 31, 2019, 08:45
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Quote:
Originally Posted by carye View Post
Hi, everyone here, I have some questions about the default fvOptions of explicitPorositySource.

What I was trying to solve was a tube reactor filled with catalyst,
so I applied a explicitPorositySource to simulate the DarcyForchheimer law.
The result seems very good and no problem.
But when I reading the code, I was confused.

I found a reference called "Porous Media in OpenFOAM" written by Haukur Elvar Hafsteinsson.
In the file, he gave the momentum equation like


in which the Si represents the porous resistance calculated by explicitPorositySource,
and there is a porosity(Gamma) appearing in the time derivative term.

However, the code of the solver is like

in which the time derivative term do not contain the porosity.

So, does anyone know why is this?
Does this mean that if I want to simulate a porous media, I just set the explicitPorositySource,
and do not need to modify the time derivative term in other equations such as the mass and species and energy equations?

Thanks

Hi,


I have a similar question. In fvOptions, we have the option to define the Darcy and Forcheimer coefficients for the momentum sink term, as well as the porosity (Gamma) which appears in the time derivative term. However, I noticed that by specifying various different porosity ranging from 0.5 to 0.99, there is no change in the solution. So, does this mean that the porosity defined in fvOptions is not used in the time derivative term of a transient solver (i.e. pimpleFoam)??


B.R.
Honey
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Old   August 9, 2019, 03:24
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Hi,

Which fvOptions you used?
I used explicitPorositySource, and found that I have nowhere to specify porosity (Gamma).
The only coefficients I can change is d and f and coordinateSystem.

if you change the Darcy and Forcheimer coefficients accordingly when porosity changes, then the solution should change, such as the pressure drop.
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