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-   -   Plotting unstructured grids in FAST ?? (http://www.cfd-online.com/Forums/main/4172-plotting-unstructured-grids-fast.html)

Radhika Gupta December 3, 2001 19:54

Plotting unstructured grids in FAST ??
 
Hello,

Does anybody knows, in format do we need the data to plot an unstructured grid in FAST. Right now I have the number of nodes, with there x y z coordinates and the number of elements (quadrilaterals) with their connectivity.

any help asap, will be really appreciated.

regards,

-Radhika

Pete December 4, 2001 08:40

Re: Plotting unstructured grids in FAST ??
 
I believe FAST (at least the last version I used several years ago) can only handle unstructured grids comprised of triangular/tetrahedral elements. If your quadrilateral grid is I-J ordered you can use the structured PLOT3D format, otherwise you would have to subdivide your elements for the sake of plotting or use another, more flexible package.

Radhika Gupta December 4, 2001 09:36

Re: Plotting unstructured grids in FAST ??
 
Let's assume that I have triangles aswell of I-J-K order. Now when I try to write in PLOT3D format, the manual specifies some flags for the triangles. I could not understand the significance of the same.

So I give all of them a value of 1 or 2. I do not get the same type of grid I am expecting. Some corners are missing or some last elements seems to be joined with middle elements.

Pete December 4, 2001 09:52

Re: Plotting unstructured grids in FAST ??
 
Just a guess, but it sounds like with PLOT3D format you may inadvertently be specifying a blanking with the "1" and "2" values you're using, or the I-J ordering isn't quite right. Plotting as a structured grid you shouldn't see any diagonal lines.

FAST also has an unstructured format you can look into, check the manual for:

Grid file:

# nodes, # tri faces, # tetrahedra (x,y,z), i=1,# nodes (triangle connectivities), i=1,# tri faces(tri face boundary conditions), i=1,# tri faces (tetrahedra connectivities), i=1,# tets

The Q file is similar to PLOT3D format, except the Q arrays goes from 1 to # nodes.

That's about all I remember, it's been a while. Good luck!

Abhijit Tilak December 9, 2001 20:24

Re: Plotting unstructured grids in FAST ??
 
Hi

Consider using GMV. It can plot any damn thing as long as u give correct connectivity information. GMV is available on majority of platforms. I don't remember the web page addess but u can search thru google. hope this helps. Abhijit


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