40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  COMSOL elog  Not logged in ELOG logo
Entry  Mon Jul 8 15:47:23 2013, Emory Brown, Optics, General, Meshing error when varying geometry 
    Reply  Mon Jul 8 18:39:31 2013, Matt A., Optics, General, Meshing error when varying geometry 
    Reply  Mon Jul 8 19:04:35 2013, Matt A., Optics, General, Meshing error when varying geometry SimpleCylinder.mph
       Reply  Tue Jul 9 14:45:04 2013, Emory Brown, Optics, General, Meshing error when varying geometry Eigenfrequency.png
Message ID: 49     Entry time: Mon Jul 8 18:39:31 2013     In reply to: 48
Author: Matt A. 
Type: Optics 
Category: General 
Subject: Meshing error when varying geometry 

Quote:

 I attempted to run the Matlab code built last week, but received an error that the mesh failed to generate on the inner domain/failed to respect edge element on geometry edge.  The error occurred on the second computation with ratioR=0.2, but for ratioR=0.1 the simulation completed successfully.  I reproduced the error in COMSOL and noted that for meshes with size at least as course as "course" or extremely fine, a mesh could be constructed, but for sizes in between an error was returned.  This region of sizes which throw errors varies for different values of ratioR.  By specifying an edge selection of the central line running down the frustum and another along the top edge of the inner cylinder and meshing points on those edges first the rest of the meshing is forced to use those nodes as a seed.

I also noted our COMSOL model had an error: ratioR was applied to the wrong face.  This was corrected as was the .m file.

I added an eigenfrequency study and ran it for several values of ratioR, obtaining the following:

ratioR Lowest Drumhead mode (Hz) Lowest Butterfly mode (Hz)

0.1 3624.8 3802.4

0.3 4375.9 3785.4

0.5 4366.5 3650.0

.75 3709.0 3041.85

1 3000 2186.3

1.1 2736.2 1893.0

1.3 2247.6 1426.4

 

The mirror's front face is 0.17 [m].  Its Gaussian beam size is 0.0156 [m].  Its height is given by 0.01734[m^3]/(R^2*(1+ratioR+ratioR^2)) such that when the two faces have the same radii it is 0.2 [m] long.

 Great Emory,

Can you put these in a plot so it's easier to read?

ELOG V3.1.3-