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-   -   Buoyancy driven flow of an incompressible fluid in a closed volume (https://www.cfd-online.com/Forums/openfoam-solving/157096-buoyancy-driven-flow-incompressible-fluid-closed-volume.html)

Nicole July 20, 2015 05:49

Buoyancy driven flow of an incompressible fluid in a closed volume
 
Good day,

I am trying to solve for the steady state buoyancy driven flow field of an incompressible fluid in a closed volume. The density variations are a bit high (5-10%) for me to use the Boussinesq approximation (I think?), and seeing as I want to add more regions later, I am using chtMultiRegionSimpleFoam.

I have a fundamental problem, however, because my domain is fixed, so normally the pressure would be adjusted to conserve mass within the volume, however my fluid is incompressible (icoPolynomial equation of state: it's density is only a function of temperature and not pressure), therefore this cannot be done.

Someone has suggested adding a small hole somewhere non-consequential in my domain to allow for inflow and outflow to conserve mass during the iterations to steady state, and hopefully at steady state there will be no net flow.

Has anyone else has experience doing this? Has anyone tried this solution?

In reality, the surface of the liquid will move depending on the temperature, I am not keen to try and implement a moving mesh for this simple problem though, so I am looking for a simpler solution - if possible!

calf.Z March 12, 2019 22:24

Quote:

Originally Posted by Nicole (Post 556126)
Good day,

however my fluid is incompressible (icoPolynomial equation of state: it's density is only a function of temperature and not pressure), therefore this cannot be done.

So if density is changed with temperature but it is not related to pressure, it is still a incompressible problem?

I think the defference between incompressible and compressible is density is constant or not. Thank you.


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