[tjim]

Hello,

I'm trying to run a CGNS mesh from the 2nd AIAA Sonic Boom Prediction Workshop. However, I am having issues identifying the boundary markers within a CGNS file.

I've not used a CGNS mesh before so I had a look through the CGNS documentation but it seems that there are a lot more markers than I anticipated in my file. Within the ZoneBC section of the file, I see a sequence running from TRI_bdy1 to TRI_bdy46, and also a further 3 QUAD_bdy markers. I am unsure what to set for MARKER_EULER, MARKER_FAR, and MARKER_SYM within my SU2 cfg file. Please, could anyone help shed a little light on this?

I just realised that the NASA larc ftp server has gone down - the mesh was originally accessed on here. I have uploaded the mesh file up here instead.

Thank you and kind regards,
Tim

[tsevine]

Hi Tim,

As far as i know when you run your config file (SU2_CFD foo.cfg) containing your CGNS mesh, it shows the boundary markers before starting iterations.. You can check it from there..

---------------------- Read Grid File Information -----------------------
Two dimensional problem.
230336 points.
2 surface markers.
512 boundary elements in index 0 (Marker = airfoil).
1408 boundary elements in index 1 (Marker = farfield).
229376 quadrilaterals.


Like this example. Then program will give error due to non-existance of BC for that markers. Then you can apply proper BC..

If thats your problem it can help.
Best
Tansu

[tjim]

Thanks for the suggestion, Tansu. Unfortunately, it seems that this file doesn't list any specific boundaries - does this mean that none are actually applied? In this case, I have no idea why there are so many elements in the ZoneBC section of the file.

I've posted the output I get below:

------------------- Config File Boundary Information --------------------
Euler wall boundary marker(s): BODY.
Far-field boundary marker(s): FARFIELD.
Symmetry plane boundary marker(s): SYMMETRY.

---------------------- Read Grid File Information -----------------------
Reading the CGNS file: ../1_mesh/delta-split-mixed-000a-170m-200s.cgns.
CGNS file contains 1 database(s).
Database 1, Base: 1 zone(s), cell dimension of 3, physical dimension of 3.
Zone 1, Zone: 695709 vertices, 2830575 cells, 0 boundary vertices.
Reading grid coordinates.
Number of coordinate dimensions is 3.
Loading CoordinateX values.
Loading CoordinateY values.
Loading CoordinateZ values.
Number of connectivity sections is 51.
Loading section Elem_TETRA_4 of element type Tetrahedron.
Loading section Elem_PENTA_6 of element type Prism.
Loading section TRI_bdy    1 of element type Triangle.
Loading section TRI_bdy    2 of element type Triangle.
Loading section QUAD_bdy    2 of element type Quadrilateral.
Loading section TRI_bdy    3 of element type Triangle.
Loading section TRI_bdy    4 of element type Triangle.
Loading section TRI_bdy    5 of element type Triangle.
Loading section QUAD_bdy    5 of element type Quadrilateral.
Loading section TRI_bdy    6 of element type Triangle.
Loading section TRI_bdy    7 of element type Triangle.
Loading section TRI_bdy    8 of element type Triangle.
Loading section TRI_bdy    9 of element type Triangle.
Loading section TRI_bdy   10 of element type Triangle.
Loading section TRI_bdy   11 of element type Triangle.
Loading section TRI_bdy   12 of element type Triangle.
Loading section TRI_bdy   13 of element type Triangle.
Loading section TRI_bdy   14 of element type Triangle.
Loading section TRI_bdy   15 of element type Triangle.
Loading section TRI_bdy   16 of element type Triangle.
Loading section QUAD_bdy   16 of element type Quadrilateral.
Loading section TRI_bdy   17 of element type Triangle.
Loading section TRI_bdy   18 of element type Triangle.
Loading section TRI_bdy   19 of element type Triangle.
Loading section TRI_bdy   20 of element type Triangle.
Loading section TRI_bdy   21 of element type Triangle.
Loading section TRI_bdy   22 of element type Triangle.
Loading section TRI_bdy   23 of element type Triangle.
Loading section TRI_bdy   24 of element type Triangle.
Loading section TRI_bdy   25 of element type Triangle.
Loading section TRI_bdy   26 of element type Triangle.
Loading section TRI_bdy   27 of element type Triangle.
Loading section TRI_bdy   28 of element type Triangle.
Loading section TRI_bdy   29 of element type Triangle.
Loading section TRI_bdy   30 of element type Triangle.
Loading section TRI_bdy   31 of element type Triangle.
Loading section TRI_bdy   32 of element type Triangle.
Loading section TRI_bdy   33 of element type Triangle.
Loading section TRI_bdy   34 of element type Triangle.
Loading section TRI_bdy   35 of element type Triangle.
Loading section TRI_bdy   36 of element type Triangle.
Loading section TRI_bdy   37 of element type Triangle.
Loading section TRI_bdy   38 of element type Triangle.
Loading section TRI_bdy   39 of element type Triangle.
Loading section TRI_bdy   40 of element type Triangle.
Loading section TRI_bdy   41 of element type Triangle.
Loading section TRI_bdy   42 of element type Triangle.
Loading section TRI_bdy   43 of element type Triangle.
Loading section TRI_bdy   44 of element type Triangle.
Loading section TRI_bdy   45 of element type Triangle.
Loading section TRI_bdy   46 of element type Triangle.
Successfully closed the CGNS file.

Loading CGNS data into SU2 data structures.
Three dimensional problem.
2830575 interior elements.
695709 grid points.
49 surface markers.
398 boundary elements in index 0 (Marker = TRI_bdy1).


Error in "short unsigned int CConfig::GetMarker_CfgFile_TagBound(std::string)": 
-------------------------------------------------------------------------
The configuration file doesn't have any definition for marker TRI_bdy1
------------------------------ Error Exit -------------------------------

[tjim]

In case it helps anyone and to follow up, I believe that the boundary conditions (if any were indeed applied) were for a different solver. I loaded the mesh into Pointwise and reapplied the FAIRFIELD, BODY, and SYMMETRY boundary conditions.

Interestingly, SU2 seems to interpret triangles and quads separately and automatically appends 'tri_' and 'quad_' to the BC markers. For this mesh to run, I had to specify the following in my configuration file:

% ----------------------- BOUNDARY CONDITION DEFINITION -----------------------%
%
% Marker of the Euler boundary (0 implies no marker)
MARKER_EULER= ( BODY )
%
% Marker of the far field (0 implies no marker)
MARKER_FAR= ( quad_FARFIELD, tri_FARFIELD )
%
% Marker of symmetry boundary (0 implies no marker)
MARKER_SYM= ( quad_SYMMETRY, tri_SYMMETRY )

Good luck and good day,
Tim