OK.. so I got it sort of blinking it's eyes a bit with a simple square enclosure in cartesian coordinates.

The trick was:

    ebc_1 = {'name':'dummy', 'region':'Surface', 'dofs':{}}

Without name, region and dofs, it failed. But dofs could be an empty dictionary ;-)

I've attached the first 12 modes it found which had frequencies of:

acoustics: [  5.16299658e-15   9.87028804e-04   9.87030371e-04   1.97418121e-03
   3.94889296e-03   3.94891183e-03   4.93646164e-03   4.93648482e-03
   7.89997828e-03   8.88811411e-03   8.88821885e-03   9.87626416e-03]

Compared with the theoretical values of 

n m f
0 0 0.0
0 1 0.000986960440109
0 2 0.00394784176044
0 3 0.00888264396098
1 0 0.000986960440109
1 1 0.00197392088022
1 2 0.00493480220054
1 3 0.00986960440109
2 0 0.00394784176044
2 1 0.00493480220054
2 2 0.00789568352087
2 3 0.0128304857214
3 0 0.00888264396098
3 1 0.00986960440109
3 2 0.0128304857214
3 3 0.017765287922

I think they looks pretty good!

There is one mystery... what is that mode with 0.009876, it doesn't *look* like a 3-1 mode... but who knows!

Anyway.. thanks for the tips... now I'll try to work out the cylindrical case.

-steve




On Wednesday, June 6, 2012 4:17:47 PM UTC-6, Robert Cimrman wrote:
The code checks that certain keywords are not missing. Try using ebcs = {} in the input file.

r.