Meshing
Start Gmsh and create the mesh with:
gmsh -3 t4.geo
Possible output
Start Gmsh and create the mesh with:
gmsh -3 t4.geo
Info : Running 'gmsh -3 t4.geo' [Gmsh 4.0.4, 1 node, max. 1 thread]
Info : Started on Mon Nov 12 12:38:17 2018
Info : Reading 't4.geo'...
Info : Done reading 't4.geo'
Info : Meshing 1D...
Info : Meshing curve 1 (Line)
. . .
Info : Meshing curve 120 (extruded)
Info : Done meshing 1D (0.03125 s)
Info : Meshing 2D...
Info : Meshing surface 24 (Plane, Delaunay)
Info : Blossom: 1734 internal 168 closed
Info : Blossom completed (0.03 s): 590 quads 0 triangles 0 invalid quads 0 quads with Q < 0.1 Avg Q = 0.741 Min Q 0.391
Info : Meshing surface 49 (extruded)
. . .
Info : Meshing surface 126 (extruded)
Info : Done meshing 2D (0.0625 s)
Info : Meshing 3D...
Info : Meshing volume 1 (extruded)
Info : Done meshing 3D (0 s)
Info : Optimizing 3D mesh...
Info : Done optimizing 3D mesh (0 s)
Info : 1358 vertices 2344 elements
Info : Writing 't4.msh'...
Info : Done writing 't4.msh'
Info : Stopped on Mon Nov 12 12:38:18 2018
Opening t4.msh
will show something similar to:
As can be seen, the Recombine
command generates both triangles as well as quadrangles on the surface. This results in different prisms. Also, we can see a huge difference in cell volumes: close to the edge the elements are much larger than close to the smooth curves.
Copying mesh
Again, to make sure the mesh file will not be overwritten by the results, we copy and rename the files:
cp t4.msh t4d.msh
Converting to dolfyn input
We now convert the mesh into *.cel
, a *.vrt
, a *.bnd
, and optionally an *.inp
file using gmsh2dolfyn
, and selecting the correct file to convert, in our case: t4d
.
gmsh2dolfyn t4d
Possible output
Start gmsh2dolfyn converter with:
gmsh2dolfyn t4d
Gmsh2Dolfyn: Converts a Gmsh mesh file to Dolfyn format.
Input must be in Gmsh version 2.0, 2.1, 2.2 or 4 ascii format.
Opening the Gmsh file
File t4d.msh opened
Reading MeshFormat
MeshFormat: 4 0 8
Reading PhysicalNames
Name 2 -> Swall
Name 3 -> Sin
Name 4 -> Sout
Name 5 -> Ssym1
Name 6 -> Ssym2
Name 1 -> Fluid
Entities
Entity 24 surface 5 Ssym1
. . .
Entity 126 surface 6 Ssym2
Entity 1 volume 1 Fluid
Physical entities found 23
Reading Nodes
Number of entity blocks: 103 Nodes: 1348
Creating the dolfyn .vrt file
File t4d.vrt opened
Point 1 Node 1
. . .
Surface 126 Nodes 506
Nodes written 1348
Gmsh 4: Total Gmsh Entity Blocks to be read in: 23
Gmsh 4: Total Gmsh elements to be read in: 1938
Creating the dolfyn .cel and .bnd files 14 23
File t4d.cel opened
File t4d.bnd opened
Element 24 Ssym1 Type 3 590
. . .
Element 1 Fluid Type 5 590
Quad boundaries: 1348
Hexahedral cells: 590
Writing the .inp file
File t4d.inp opened
inp: 2 Swall T
inp: 3 Sin T
inp: 4 Sout T
inp: 5 Ssym1 T
inp: 6 Ssym2 T
Done gmsh2dolfyn 2018
Running Pre-Processor
Now we will run the pre-processor.
dolgeo -s 1.0 -b t4d
If no options are given with the dolgeo
command, you will be prompted for them. Fill in case name t4d
, scaling factor of 1.0
(default) and bin
as format of geometry file.
Possible output
The pre-processor is run with:
dolgeo -s 1.0 -b t4d
Dolfyn PreProcessor
t4d T T T F
Using command line arguments
Using t4d as input
Opening vertex file
Initialise vertex list
. . .
Region ID: 2 => Swall
Region ID: 3 => Sin
Region ID: 4 => Sout
Region ID: 5 => Ssym1
Region ID: 6 => Ssym2
Type 1 regions found: 5 6
WARNING: check inp-file
Using: 1.00000000 binary
Dump binary geometry file
Done
Running Simulation
Finaly we will run the dolfyn simulations.
dolfyn t4d
If no case name is inputted directly, you will be prompted. If so, enter case name t4d
.
Possible output
The pre-processor is run with:
dolfyn t4d
This is dolfyn version 0.607
Copyright(C) 2002-2016 Cyclone Fluid Dynamics BV
NL-5583 XM, Waalre, The Netherlands
see http://www.cyclone.nl and https://www.dolfyn.net
Using Sparsekit2 by Yousef Saad
(C) 2005, the Regents of the University of Minnesota
Modules with patches (C) 2004-2010 by B. Tuinstra
see http://www.home.zonnet.nl/bouke_1/dolfyn
Tecplot interface (tecplt.f90) (C) 2006-2012 by
S.B. Kuang, UNSW, Sydney, Australia
VTK interface updated (C) 2007 by J. Jacobs
Static boundary conditions (C) 2011 by J. JoJo
MKL contributions and suggestions by Runar
Using case: t4d
Calling dolfyn t4d .dge
t4d.dge binary
. . .
Number of requested steps done. 200
Opening restart file
File t4d.rst
Restartfile 400 written
Writing Full Gmsh file...
Done
Maximum change in PP: 1.17175070E-07 1357.51599 9.99999975E-05
Arrays cleaned up
Done t4d
Bye!
That’s it! Now all the calculations have been carried out, we can start to analyze the output.