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-   -   Grid softwares for VOF simulations (http://www.cfd-online.com/Forums/openfoam-meshing/61605-grid-softwares-vof-simulations.html)

openfoam_user November 4, 2008 06:50

Dear OF-users, I am trying
 
Dear OF-users,

I am trying to compute VOF simulations around ships using the rasInterFoam solver.

I have used the main settings of E. Patterson (wigley hull) with another geometry.

But the case is crashing after a few iterations, maybe due to the quality of the mesh.

I use ICEMCFD Hexa for grid generation.

I was wondering what other grid softwares are used by the other users of OF (for complex geometries like cars, aircrafts and ships) ?

All comments about grid softwares and how to set-up VOF simulations around ships are welcome.

Regards,

Stephane.

eugene November 4, 2008 08:40

The general purpose meshing to
 
The general purpose meshing tool shipped with OPENFOAM 1.5 is snappyHexMesh.

openfoam_user November 4, 2008 11:12

Hi Eugene, do you know a tu
 
Hi Eugene,

do you know a tutorial for snappyHexMesh with complex geometry ?

Stephane

anders November 5, 2008 08:07

Hello Stephane, I'm working
 
Hello Stephane,

I'm working on the same type of computations. I also experienced that the solver crashed with the wigley tutorial settings on a realistic hull. I had to change the scheme to more upwind weighting. I got convergence with the following settings.



divSchemes
{
div(rho*phi,U) Gauss upwind;
div(phi,gamma) Gauss upwind;
div(phirb,gamma) Gauss interfaceCompression;
div(phi,k) Gauss upwind;
div(phi,epsilon) Gauss upwind;
div(phi,R) Gauss upwind;
div(R) Gauss linear;
div(phi,nuTilda) Gauss upwind;

div((nuEff*dev(grad(U).T()))) Gauss linear;
}


laplacianSchemes
{
default Gauss linear corrected limited 0.5;
}


I have not yet compared the computed drag with my own CFD solver, so I don't know if it gives to mush diffusion to the solution.

Anders

openfoam_user November 5, 2008 08:35

Hi Anders, Thanks. I will t
 
Hi Anders,

Thanks. I will try your settings and give you a feedback asap.

Which software do you use for mesh generation ?

Have you tried snappyHexMesh ?

Stephane.

anders November 5, 2008 09:40

Stephane, I use an in-house
 
Stephane,

I use an in-house gridgenerator where I have developed an efficient parametric template for ship hulls. However I have not yet succeeded in converting meshes from our format to the OpenFOAM grid format (work in progress...).

The only ship hull I have yet computed in OpenFOAM was generated by the StarCCM+ software.

I have not yet had time to look in to the snappyHexMesh utility.

Anders

vinz November 5, 2008 14:25

Hi Stephane, On our side we
 
Hi Stephane,

On our side we use GridPro to create meshes around ships and planes.
We created a converter from GridPro to OpenFOAM which is available on the forum and works for a large band of cases (still needs some code implementation for periodic boundary conditions).
I did not make computations on ships but some clients did.
If you want some other information, do not hesitate to contact me.

Hope that helped.

Regards

openfoam_user November 6, 2008 03:35

Dear Anders, dear Vincent,
 
Dear Anders, dear Vincent,

GridPro are among the best grid softwares with ICEM and Gridgen.

I am a new user of OpenFOAM. And maybe beginning with free surface computations is not the simplest thing.

I have done meshes around ship with ICEM hexa. The quality seems good, but the computation crashes after some iterations.

I have download the mesh of E. Patterson (wigley hull) and his settings. The case runs well. Just changing the geometry make the case crashes after less than 10 iterations.

Stephane.

vinz November 6, 2008 04:17

Hi Stephane, I don't know i
 
Hi Stephane,

I don't know if your geometry is very confidential.
But if it's not, i can give it a look and try to do a mesh so you can try a different mesh generator and see if it's coming from that or not.
If you want, just send me an email, so we can arrange everything.

Vincent


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