[alexandrepereira]

Hi Forum,

I am trying to use gmsh as a mesh generator for a specific cfd problem:

Creating an EXTERNAL mesh around a car shape.

My project has been built in a CAD package as an stl.

I can import it inside gmsh, but i do not ( yet ) know how to define a fluid domain inside gmsh but that, is the least of my problems; by what i have seen in the gmsh tutorial, i simply have to define points, edges, and faces sp as to create my rectangular virtual "wind tunnel" with dimensions such as to have the least blockage in my simulations... my worse problem will be how to "subtract" the volume corresponding to my stl car from that of the fluid domain, and then mesh it ( preferably with a boundary layer ) and then impose suitable BCs...

So, I ask you forum:

1. Is it possible to "subtract" a volume defined by an stl boundary from another volume created inside gmsh, or do i have to sculpt and carve the car shape using gmsh scripting language ( a bit untractable i guess ...) ?

2. CFD calculations are critically dependent on appropriately meshing a boundary layer with the due refinement so as to capture the high gradients in that region; is this possible in gmsh ?

3. Should i fail ( hope not ) in my task to use gmsh to build an OpenFOAM mesh to use in my simulation, what would you users suggest me to use as a mesher ? Gridgen, Pointwise, Harpoon, IcemCFD, netgen, tetgen...?

BTW i would like a mesher that best suits my needs in CFD... Boundary layer meshing... etc. what would be yr suggestion?

Thanks in advance,

Alex

[bernd]

I think you can perform the volume subtraction using cellSet.
See also http://www.cfd-online.com/OpenFOAM_D...es/1/7543.html

Bernd