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-   -   To solve my own equation (https://www.cfd-online.com/Forums/openfoam-solving/59760-solve-my-own-equation.html)

 lam March 23, 2007 07:06

Hi Rafal, As you said to me

Hi Rafal,

As you said to me it was possible, I create my own equation in Foam.
In icoFoam.C, I moved the Navier-Stokes equation for a another eqution easier:

In th eicoFoam.C, I wrote this line below:
********************************************
fvVectorMatrix UEqn
(
fvm::laplacian(nu, U)
);
**********************************************

And I changed anything else, in any files
(of course, I made the ./Allmake)
But I had a wrong solution, when did:

icoFoam SFOAM_RUN/tutorials/icoFoam MyCavity
(MyCavity is a case that I created, diferent from the "cavity" case).

My solution is actually:

************************************************
Time = 0.01

Mean and max Courant Numbers = nan nan
ICCG: Solving for Ux: solution singularity
ICCG: Solving for Uy: solution singularity
ICCG: Solving for Uz: solution singularity
ICCG: Solving for p: solution singularity
time step continuity errors : sum local = nan, global = nan, cumulative = nan
ICCG: Solving for p: solution singularity
time step continuity errors : sum local = nan, global = nan, cumulative = nan
ExecutionTime = 0.75 s ClockTime = 1 s
************************************************

I know there is somethin wrong with the timeStep here. But I do not know what and where I have to cahnge things to solve my problem!

Can you, or someboby else, give me some advice?

Lam

 rafal March 23, 2007 07:36

Hi Lam, there can be many c

Hi Lam,

there can be many causes of solution singularity.
Several thing that I can see here.
- you removed time derivative and you try to solve

- the equation now is diagonally equal
(since diffusion term produce diagonally equal
matrix; grad(p) is source term) and matrix
has to be diagonally dominant to solve it.

these are my quick ideas (i can be wrong)
rafal

 lam March 23, 2007 08:30

Thamks Rafal to reply me, I

Regards,

Lam

 lam March 28, 2007 06:04

Hi world! I did a big mista

Hi world!

I did a big mistake, I delete by accident my doc/Doxygen/html!!
How can I get it again???

Lam

 rafal March 28, 2007 06:21

you can untar OF project in OT

you can untar OF project in OTHER directory
than ~/OpenFOAM. and than move it to right place:
i.e:
\$ mkdir other
\$ cd other
\$ tar -xzf /path/to/OpenFoam-1.3.General.tgz #not sure of name here
\$ mv other/OpenFOAM-1.3/doc/Doxygen ~/OpenFOAM/OpenFOAM-1.3/doc
\$ cd ..
\$ rm -rf other
this should work
rafal

 lam March 28, 2007 09:35

Oki, Rafal! You're right!

Oki, Rafal!

You're right!
Thanks a lot!

Lam

 lam March 29, 2007 07:30

Hi world, I'm wondering mys

Hi world,

I'm wondering myself again about simpleFoam.C

I noticed that I could put the turbulence in "off":
but what kind of equation will I solve as result?

Somebody can help me?

Lam

 lam March 30, 2007 03:37

HEY, everyone! Nobody can g

HEY, everyone!

Nobody can give me some advice?

Cheers,

LAm

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