[Gmsh] Industrial Applications of Intermediate Complexity

[Jacques Kools]

Hallo Everybody,
 
I have been using GMSH/GetDP for a while for an industrial application with intermediate complexity ( 3D Non-linear magnetostatic field calculations for sputter magnetron designs) . We have experience doing similar simulations with 3 different commercial packages for the same application, and I continue to be impressed by GMSH/GetDP. Great Job ! 
 
I wanted to give you guys some feedback and formulate a few suggestions:
 
1) I think the geometry editing , postprocessing, coupling with the solver and GUI are great. 
 
       a)  I have attached an example to illustrate the quality of the results that I get from GMSH/GetDP and the level of complexity of the models that I am working with. This is representative for a real problem for this application ( see also  http://www.integratedsoft.com/papers/techdocs/tech_7ax.pdf) , and the results are similar to the ones obtained with the commercial packages.       
 
     b) It would be useful at times to have an  "unclick" option in the GUI, especially for complex 3D geometries: If you have to select a large number of objects in a complex model ( e.g. to define a surface loop), you might click on the wrong surface. If you can just unclick the last object, you do not have to start all over again.
 
      c) I find that the communication between GMSH and GetDP is not always working from the first time under Windows, but it works well under Linux. (Very minor issue)
 
2) I find that, as you warned in the introduction of the manual, that the 3D meshing algorithm becomes the time limiting step for this kind of calculations (not the solver ). I looked into this a little bit and noticed the following: 
      During the last step of the 3D meshing ( when something is converging to 0.8), the memory allocation of the program increases substantially. For example, while calculating a mesh with a final size of about 20-30MB, the program has several hundreds of MB allocated at some time ! On a windows box ( especially the ones with low DRAM) the OS becomes unstable, while Linux starts using the hard drive as overflow,  decreasing the speed with a factor of 100 or so !! 
 
Here's my question : Could it be that there is some redundant memory allocation during that step ? (I noticed a hint of a similar issue in 2D in the release notes of version 1.31. ). 
 
It would be nice if I can refine the meshes by a factor 2 or so ( you can see that the pictures are still a bit grainy), but that is at the moment a bit unpractical on typical present day PC's (1GB). Of course, I can always use some of the money that I saved to buy more memory,...
 
I hope this is useful,
 
Jacques 
 
 

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