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Old   June 18, 2012, 05:17
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Hello, I am using the case buoyantboussinesqpimplefoam and I would like to add concentration, as I can do it?

I have seen I have to follow the steps as in the tutorial to add temperature, but the equations are not the same, which ones I have to wear?

I am new to OpenFOAM and I would like someone to help me.

thanks!
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Old   May 24, 2016, 21:25
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Quote:
Originally Posted by libia87 View Post
Hello, I am using the case buoyantboussinesqpimplefoam and I would like to add concentration, as I can do it?

I have seen I have to follow the steps as in the tutorial to add temperature, but the equations are not the same, which ones I have to wear?

I am new to OpenFOAM and I would like someone to help me.

thanks!
Hi,
Have you found the solution?
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Old   May 24, 2018, 09:51
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PATRICIA NAKANWAGI
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How were you able to add concentration in buoyantBoussinesqPimpleFOAM
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Old   May 24, 2018, 12:12
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The differential equations for heat transfer and mass transfer are the same. You may set concentration as temperature. The thermal diffusity is equvalent to the diffusion coefficient. You may model the changes in fluid weight by concentration loss (at boundaries) too.

The problem I has is that temperature driven density changes and the thermal diffusity are much higher in comparision to mass transfer. It is numerical more demanding to calculate mass transfer.

I got giant problems combinating free convection (fluid motion driven by density changes) with external flow, if I used coefficients typical for mass transfer.
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Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950)
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Old   May 25, 2018, 07:15
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PATRICIA NAKANWAGI
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Thank you Piu58,


My challenge is with trying to add concentration in buoyantBoussinesqPimpleFOAM.
I am working on a case in which I am using the boussinesq approximation with density a function of both temperature and salinlity.

The temperature scalar is already in the solver, need to add salinity too.
kindly seeking some guidance on how I can be able to do this.


Thank you
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Old   May 25, 2018, 12:12
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The temperature scalar is already in the solver, need to add salinity too.
kindly seeking some guidance on how I can be able to do this.


Thank you
You have to run the simulation twice, one for the temperature and one for the salinity. If the flow is (mainly) driven by one of them, you may simulate the second by scalarTransportFoam with the solution of the first.
Mostly, it is not a good idea to put all the physics in one simulation. If there ist a way to split it, do.
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