Physical Tag To Mesh Elements
 

Hi,

I am using Gmsh for creating structured 2d meshes of quadrilaters (by defining Transfinite Lines and then Transfinite Surfaces).
Is it possible (and if yes, how?) to assign a "Physical Tag" to a specific group of elements of the mesh? and how about specific edges of the mesh?
Indeed, my goal is to export the ".msh" output file (version 2.2) and to let the (external) solver know if some elements of the mesh must be considered as obstacles in a fluid flow.
I know how to assign Physical Tags to Geometrical Elementary Entities... but not to Mesh Elements. Is this possible?
I would like not to modify manually the ".msh" file to define these tags.

Thanks,
Best Regards,

Francesco L. Romeo

p.s. I would prefer not to insert holes in the mesh to define the obstacles, because my solver uses a "direct addressing mode" (indirizzamento diretto) for Carthesian 2d meshes...