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-   -   Missing gravity in new Teqn in compressibleInterFoam, OpenFOAM v2.2.0 (https://www.cfd-online.com/Forums/openfoam-solving/114234-missing-gravity-new-teqn-compressibleinterfoam-openfoam-v2-2-0-a.html)

 dduque March 7, 2013 09:29

Missing gravity in new Teqn in compressibleInterFoam, OpenFOAM v2.2.0

Hi everybody.

We were greatly pleased by the modifications in compressibleInterFoam introduced in the new OpenFOAM v2.2.0 release. We were precisely working in extending the EOS to include non-isoT simulations, and the task is now basically done for us.

However, I notice the equation for temperatura in the new Teqn.H reads:

Code:

```      fvm::ddt(rho, T)       + fvm::div(rhoPhi, T)       - fvm::laplacian(kByCv, T)       + p*fvc::div(phi)*(alpha1/Cv1 + alpha2/Cv2)```
Don't you have a term

rho g·u / c_v

on the right hand side of this eq?

This is the power production due to gravity (well, rho g·u is the power, divided by c_v gives a temperature variation).

Thanks. Best,

Daniel

 dduque March 11, 2013 10:42

No answers? Well, I'll try to implement it myself, while listening to this tune: Gravity's Gone.

 dduque March 12, 2013 07:59

OK, I have just modified Teqn.H to solve this equation, including the
gravity power term, and it seems to be working.

Code:

```    solve     (         fvm::ddt(rho, T)       + fvm::div(rhoPhi, T)       - fvm::laplacian(kByCv, T)       + p*fvc::div(phi)*(alpha1/Cv1 + alpha2/Cv2)         - rho*(U & g) *(alpha1/Cv1 + alpha2/Cv2)     );```
Best.

 markusrehm March 12, 2013 17:26

Hi Daniel,

consider posting a bug report to the Mantis:

http://www.openfoam.org/mantisbt

I am not sure if the developers follow the forum.

Markus

 dduque March 20, 2013 14:50

Actually, I was wrong: there is NO gravity term in the energy equation. At least, in this energy equation. There is one in the conservation version of the energy equation (for E=rho e + rho u^2/2), but dissapears in this version. Sorry!

 alundilong June 20, 2015 23:37

Quote:
 Originally Posted by dduque (Post 415328) Actually, I was wrong: there is NO gravity term in the energy equation. At least, in this energy equation. There is one in the conservation version of the energy equation (for E=rho e + rho u^2/2), but dissapears in this version. Sorry!
Yes. However, I did not see any gravity term, rho g&U, in the "total energy form".

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