How to generate a 2D unit rod mesh:
1. Invoke ../../tool/prex to get GUI as follows:
2. choose a name, for an example "new", and type new and press return.
3. Click READ PREVIOUS PARAMETERS and type in an existing file.
[eg, type in "2d-unit" to read an existing data file "2d-unit.rea"].
(note: We are building a 2d mesh first. So use any existing 2d mesh at this stage).
4. Press return from the previous stage.
5. Click BUILD FROM FILE and press return.
6. You will see the following result from the previous step. Double-click ZOOM.
7. Zoom in by typing in two points (assume you know the coordinate range of the existing mesh that you are reading) and pressing return.
[eg, -100 -100 100 100] meaning from one point (-100,-100) to (100,100).
8. Click DELETE.
9. Click one point, approximately (-80,80) and the other point (80,-80).
10. Previous mesh is deleted from the step 8-9. However it saves the parameters from the previous mesh.
Note: you can skip all the parameter settings you needed to go through if you chose TYPE IN NEW PARAMETERS at the beginning.
Now we are ready to build a new mesh. Click SET GRID.
11. Result from 10.
12. To set POLAR coordinate from F to T: click POLAR and then click R on the Menu.
To set CARTESIAN from T to F: click CARTESIAN and then click R.
Click DIV: and then click 8 and R on the Menu. Click dR: and then click 2.5 and R on the Menu.
Press MAIN MENU.
13. Result from 12.
14. Click ZOOM (NOT: double click). Then move the mouse to the polar coordinate screen. Click one point approximately a=(-60,60) shown as the white sign '+'.
15. Click another point approximately b=(60,-60). Then click ZOOM. This will zoom in within the box frame chosen by a and b.
15. Result from 14.
16. Click four vertices by clockwise or counter-clockwise as shown. Click REDRAW MESH.
17. To generate more element, repeat 16 to make each element.
18. To generate more element, repeat 16 to make each element.
19. To generate an element with straight line in the opposite side of the curve, make radiusdifferently as shown.
Note: we want to generate mixed shape of quadlateral elements.
20. Repeat 19.
21. Click SET GRID from 19. Make CARTESIAN T and POLAR F, by clicking CARTESIAN and R, and POLAR and R. Click DX: and then click 5 and R in the Menu. Then clcik MAIN MENU.
22. Result from 21.
23. To make element 25, click the left_mouse_button for the vertices which align the Cartesian grids.
If the vertices not aligned with the cartesian grids, you click right_side_mouse_button.
24. Repeat 23.
25. Double-click ZOOM, and type in -55 -55 55 55 to adjust mesh domain range.
25. Click SET GRID. Change to POLAR T CARTESIAN F.
Make DIV 16 and then click MAIN MENU. Create the element 35 as shown.
26. Make more elements in the similar manner as the element 35.
27. Change settings from POLAR to CARTESIAN coordinate. Then press MAIN MENU.
28. Result from 27.
29. From 28, thre are some vertices which are not aligned on the Cartesian gridd.
To modify the position of the vertices, click MODIFY ELEMENT and click the point that we want to move.
Then click a new point where we want to move the original point to. Do 30-36 for the quater part of the domain. Then repeat the same procedure for the remaining part to get 37.
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37. Result from 29-37. Click END ELEMENTS.
38. Click ACCEPT MATL, QVOL.
39. Click SET BCs.
40. Click PERIODIC-AUTO.
41. Keep clicking PERIODIC-AUTO (42-47)
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49. Click ACCEPT B.C.'s.
50. Result from 49. Click EXIT. Type y if it asks periodic checking.
How to duplicate a 2d unit mesh into a 2d mesh:
51. Assume we have a unit_2d_mesh from the previous step (1-50); Domain range [-50,50]x[-50,50], named as unit-2d.rea;
Duplicate it by 4 in x direction with domain range [-250,250]x[-50,50].
cd NEKCEM/examples/sample/
../../tool/n2to2
52. Press Return Key after 51.
53. Duplicate it by 4 in y direction with domain range [-250,250]x[-250,250].
54. Press Return Key after 53. We have now a new mesh, named as solar-2d.rea
55. In order to set periodic boundary condition for solar-2d.rea. We use prex and
follow the procedures (56-66) to set the periodic boundaries in the similar manner that we have done for unit-2d.rea (detail explanation will be skipped).
Choose the name solar-2dd.rea for new mesh and then rename it as solar-2d.rea.
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How to extend a 2d mesh into a 3d mesh:
67. Generate 3D mesh unit-3d.rea for unit-2d.rea.
68. Generate 3D mesh solar-3d.rea for solar-2d.rea.
How to generate *.map file:
69. genmap for unit-3d.rea to generate unit-3d.map
70. press return key.
71. genmap for solar-3d.rea to generate solar-3d.map
72. press return key.
