[Gmsh] Time History Processing

Christophe Geuzaine geuzaine at gmail.com
Mon Jul 11 21:10:42 CEST 2005

abhishek basak wrote:
> Hi, I have a .pos file which contains the values of the caluclated 
> variables at different times (e.g. test1.pos supplied in the 
> tutorial). I want to get the time history at a particular point i.e. 
> variation of variable (e.e. temperature) w.r.t. time. How do i do it?

Hello - You can use Plugin(Probe), or Plugin(CutGrid) with nPointU=1 and
nPointsV=1. The resulting view will contain a single point, with all
the time evolution. You can either use Options->View->General->2D Time
Plot to see the time evolution in a X-Y plot, or you can export the view
in a text file (View->Save As->Text) and use an external plotting program.

> I also want to know, if it is possible to get the values along 
> differnt paths (obtained by Cut-grid) at diffent times?

Sure: you can select the time step independently in each view
(Options->View->General->Time Step).

> I also have a FEM program, which uses a 20-noded element. Can u give 
> instructions about how to add a 20-noded element into gmsh.

You will have to compile a recent cvs snapshot
(http://geuz.org/gmsh/src/gmsh-nightly-source.tgz). Recent snapshots
have built-in support for second order elements in the mesh module as
well as in the post-processing module. The second order elements
supported by Gmsh are the "complete" ones, so for a 20-node brick you
will have to add the missing degrees of freedom when writing the files
(mid-face+volume nodes). Check the doc in the cvs snapshot for more info.



Christophe Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org

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