Dear mukut,

Actually finding a grid generation tool is the first step of my thesis and right now I have no idea about the priority. I just want to find the best software. I can order it, there is no problem.

Try Salome Mecha. It has a geometry module and the mesher. It has a GUI but can be also used in batch mode (scripts). Than you will be able to export the mesh into the .unv format that can be converted to the OpenFOAM standard using the ideasToFoam utility.

Franco

Dear Sahar

You can import generated mesh files by other Commercial Software to OpenFOAM.  But the point is that all the boundaries should be named by you when you are generating mesh and the geometry, because you should apply boundary conditions in the folder of initial value and boundary values, where there must be a name for each boundary or group of boundaries However, I recommend you to use gambit, or if you use Ansys-CFX, transport the mesh to gambit, and then name the boundaries. 

P.S. The problem you are dealing with, seems to be very interesting, so enjoy it. 

Good Luck 

Dear colleague

An experienced friend in meshing proffers POINTWISE for openfoam meshing. My work with POINTWISE was excrutiating but eventuated to a structured good mesh.

hope it helps.

I would say, use snappyHexMesh from the OpenFOAM package. It is a good start and complicated meshes with many different parameters are possible. My master students have worked with it quite a bit. In one of their thesis (first link) you can find even some instructions on how to use it.

You can find some more tutorials on meshing with snappyHexMesh under holzmann-cfd.de (2nd link), he did some great work and studying these will give you a good understanding on how to make good meshes with snappyHexMesh.

http://www.diva-portal.org/smash/record.jsf?pid=diva2%3A696508&dswid=-677

http://holzmann-cfd.de/index.php/en/tutorials-en

Hi there,

use the NURBS Modelling from Rhinocerous3D to create the surfaces, and after that recreate the Model using the KUBRIX software from Itasca Inc. U will get the Jacobean correctors of the mesh.

Greeting , Dorel.

There are many open source as well as commercial grid generation packages are available. The choice is solely depends on your problem requirement, user friendly and considering less cpu time. However, i ill suggest ICEM grid generation software for complex geometry.

It's all about your preferences and the geometrical difficulties you expect to encounter. Snappy is quick to get going and manages complicated geometries, but may have some issues with boundary layer meshes; perhaps not an issue in your case. Other cell-cutting approaches works fine (and seems to produce better BL-meshes), including Star-CCM+, Hexpress, Boxer, Ansa etc. (Haven't worked with Ansa myself but from what I've heard it's a bit tough to get started and it's main strength seems to be to also handle dirty CAD). Pointwise is my suggestion if you want to have the possibility to do hybrid meshes of high quality (i.e. part of the domain structured and part unstructured).  Ansys mesher is also fine if your happy with tets+prisms. ICEM if you want a completely structured mesh (or blockMesh by all means if the geometry is not too complicated).

Good luck! Cheers!

Dear Sahar,

Grid generation is largely a matter of experience.  Although snappy mesh almost always works well, but you are allowed to use other popular soft wares(GAMBIT, CFX,..) , if you already have experience and you prefer to work with them. Then you can convert your mesh to OpenFOAM format.

Fortunately OpenFOAM accepts and has the ability to convert meshes from other soft wares (both CAD or mesh generators soft wares).  Here you may find more information:

http://www.openfoam.org/features/mesh-conversion.php

Kind regards,

I have do some study on openFoam.

my recently study was Aachenbomb , and i had to import mesh from another generate mesh tool to openFoam. I used Gambit for mesh Generating and then for importing mesh to openFoam i have used this command :

FluentMeshToFoam xxx.msh

have a good time

Hello Sahar,

If would like to use sHM the following link have some tips about how to use it. http://www.sourceflux.de/blog/

Regards

Pablo

I would recommend that you use Grid Gen which is compatible with OpenFOAM.

I have found creating the geometry and mesh in Salome (free) and exporting as a .unv file to be a good solution.  You can then use ideasUnvToFoam to convert the .unv file to the OpenFOAM format.  Salome can generate good quality hybrid tetrahedral/hexahedral meshes that work well in OpenFOAM as long as the mesh quality is sufficient (make sure max non-orthogonality is not too high).

Pointwise

snappyHexMesh is a good one, but I strongly recommend you to use Salomé Code-Aster or GMesh.

I recommend to use GMSH and you write the code like C++ to write .geo . This is the official web page and some tutorials http://geuz.org/gmsh/.

In the past I was used Salome http://salome-platform.org/user-section/about/mesh. However GMSH gave more facilities and advantage than Salome.

The best tool I recommend is GMSH. 

ICEM CFD

You might try cfMesh (http://www.c-fields.com/cfmesh).

Quite easy to configure with e.g. STL input from Salome.

I agree with Dominik. I recently tried out cfMesh and it is very simple to use. The requisites to the STL geometry are the same as that of snappyHexMesh and the configuration file is very very simple.

Hypermesh or ANSA will be best as most of the industries uses it for complicated geometries.

Several tools are recommended here. However, which one of these also provides the definition of boundaries in the mesh, like it happens in the case of Ansys Workbench. There we can define the boundary surfaces as well. Because in OpenFOAM once we import mesh we have to define the boundary based on face definition which is again cumbersome. 

I can recommend snappyHexMesh and Salome as well.

cfMesh might be the best choice. It's not perfect, but it was the best (free) I found.

I have used Salome with "ideas to foam".  This is a function built into openfoam that takes the mesh generated by Salome and converts it into a blockmesh dict file.  I am currently evaluating blender as an alternative.  Mostly because it has a larger support online, and sometimes I get concerned that Salome is going to fall by the wayside.

please note that for complex domains,  I was highly unsuccessful when trying to develop my mesh if there was a partition in my geometry.  I found that everything works best when I would setup the geometry in Salome and draw everything out point by point then convert those points to edges.  If someone had of made this available when i was first learning it would have greatly reduced the amount of time I had to spend battling the software.

http://staff.um.edu.mt/__data/assets/pdf_file/0016/106144/Salome_to_OpenFOAM.pdf

I have been using gmsh for two years and I really like it a lot. I would suggest you give it a try. You can use it to generate a complicated grids and it works for both Linux and windows.

It is more than 3 years that I'm using ICEM CFD for CFD in both OpenFoam and Fluent. It is robust and easy to use providing a full hexa mesh through O-grid concept.

for CFD in openFoam, use the following commend to convert .msh mesh to openfoam mesh.

>>

$ fluent3DMeshToFoam

I would highly recommend Pointwise. The snappy and cfMesg type packages are based on automatic mesh generation. However, the meshing based on primitive geometries (blockmesh) for the complex geometries creates troubling meshes at the boundaries. The biggest problems is the often the mesh surfaces are not perpendicular to the flow direction, and create meshes with corner that obstructs the flow and sometimes lead to high courant number as well as non convergence.

Pointwise works like gambit, where on the geometry surface we start by defining edges, nodes and then surface mesh followed by volume meshes. This way the meshes are mostly parallel to the geometry surface leading to higher chances of converged solution.

I think you may have to choose which type of meshes you would like to choose for your simulations and then decide on which the host of mesh generators ( both free and commercial) you would like to pick.

I recommend SnappyHexMesh especially for large computational domains since it is possible to generate huge computational mesh using parallel computing on multiprocessors.

Please I need help on how to link Salome, OpenFoam and Python script to communicate together if possible in real time.

Hey Mutiu,

That's a pretty general question. I would suggest you to be more specific.

I worked with Salome and Python through its module "geometry" - it is possible to create Salome geometry through this Python module.

Regarding OpenFOAM, I think you want to export a mesh right? I usually do it by exporting it to the UNV mesh format, and using the conversion tool in OpenFOAM "ideasUnvToFoam" ( if i did not mispell it).

Hope it helps

Regards

Iago

Hi all, I'm getting this following error when I tried to convert salome unv mesh to openfoam using ideasUnvToFoam --> FOAM Warning : From function Foam::polyMesh::polyMesh(const Foam::IOobject&, const Foam::Xfer&, const cellShapeList&, const faceListList&, const wordList&, const wordList&, const Foam::word&, const Foam::word&, const wordList&, bool) in file meshes/polyMesh/polyMeshFromShapeMesh.C at line 595 Found 50980 undefined faces in mesh; adding to default patch. Adding cell and face zones Face Zone inlet_water1 187 ideasUnvToFoam: ideasUnvToFoam.C:1277: int main(int, char**): Assertion `nouveau > -1' failed. Aborted (core dumped) Can I know how to sort this error?

Hello

Gmsh, Salome, cfmesh are good for OpenFOAM. But I prefer polyhedral mesh type, because reduces the time of convergency.

I would highly recommend using Gmsh. There are many good options available, as shown throughout the comments, but the simplicity and control in Gmsh are remarkable characteristics. And if it’s possible to parametrize your geometry, you could achieve very good mesh results using Gmsh python api.

We agree that cfMesh is more helpful for complex geometry (see below for reasons). Why not use a combination of meshing software appropriate for each sub-domain then 'merge' these meshes?

We found cfMesh was able to adequately mesh a complex geometry where Gmsh failed even with significant computational effort trying to draw out (iterate) some acceptable 'checkMesh' meshing parameters:

- cfMesh's approach of degrading the geometry to achieve good meshing results (using an STL file as input) was very helpful in our case.

- cfMesh's combined use of poly, tet, and hex cells in a single meshing module (e.g. when using 'cartesianMesh') we believe is even more advantages when dealing with complex geometries.

We ended using both GMSH & cfMesh within a single OF case (via merging the complementary meshes using the 'mergeMeshes' OF utility).

OpenFOAM run from IPython could achieve similar parametric control (as GMSH's Python interface) using ! and perhaps in combination with PyFoam. I don't have any financial involvement with cfMesh.