[Gmsh] Block structured hex-only-3D-mesh for sequence of conical frustums

[Florian Hoffmann]

Dear all,


I would like to generate a block structured hexaeder-only-3D-mesh for a geometry consisting of several conical frustums. Something like this:


  __________ 
  \                 /
   |               |
    \             / 
     |           |          
C_|           | _ C      
     \          /            ^  extrude B->C
B _ \____/  _ B    _|_
A _  |___|   _ A


Section A-A has a non-circular cross-section, and section B-B and all others above have circular cross-section. I successfully created A-A and the circular cross-section B-B. Both consist of several surfaces/blocks (see attached picture). In my *.geo script I try to work with variables. There I collect the IDs of all surfaces forming the cross-section B-B (= the bottom of the first conical frustum) in an array (=cross_section_BB_surfaces[]). Nevertheless, when I try to Extrude+Dilate these surfaces in order to build the first conical frustum (=B-B -> C-C), during meshing I get several errors about „Could not find extruded vertex …“ . Extrusion-only of B-B to C-C (without Dilate) works fine, but this would just give me a cylinder outline and it is not what I want.
Since I need a block structured mesh and also because A-A has a non-circular cross-section (see bottom plane of geometry in attached picture) I would really like to make use of the extrude command for creation of C-C and the other frustum above.

(1) Is there a way to make this work (without having to create all frustums including their blocked structure by hand) ?

(2) If not, can anybody think of a solution for how to script this in an efficient and handable way ?


Thanks a lot.

Cheers Flo









Mit freundlichen Grüßen
--
Dr.-Ing. Florian Hoffmann
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