Velocity potential is pretty well defined here:
http://en.wikipedia.org/wiki/Potential_flow#Description_and_characteristics
When I try to run with no boundary conditions I'm getting the error below. Does it lead to a singular matrix or something with no essential boundary conditions?
thanks! -steve
Traceback (most recent call last): File "acoustics.py", line 113, in <module> main() File "acoustics.py", line 104, in main conf = ProblemConf.from_file_and_options(filename_in, options, required, other) File "/Users/steve/Development/sfepy/sfepy/base/conf.py", line 311, in from_file_and_options override=override) File "/Users/steve/Development/sfepy/sfepy/base/conf.py", line 290, in from_file required, other, verbose, override) File "/Users/steve/Development/sfepy/sfepy/base/conf.py", line 359, in __init__ required=required, other=other) File "/Users/steve/Development/sfepy/sfepy/base/conf.py", line 369, in setup other_missing = self.validate( required = required, other = other ) File "/Users/steve/Development/sfepy/sfepy/base/conf.py", line 421, in validate raise ValueError('required missing: %s' % required_missing) ValueError: required missing: ['ebc_[0-9]+|ebcs']
On Wednesday, June 6, 2012 3:10:58 PM UTC-6, Robert Cimrman wrote:
On 06/06/2012 09:40 PM, steve wrote:
OK.. on to the eigenvalue problem.
I started with the quantum program... and stripped out all the quantum stuff. ;-)
Basically the acoustics problem is exactly the square well potential (V=0 everywhere) BUT with different boundary conditions.
In quantum_common.py we've got:
ebc_1 = { 'name' : 'ZeroSurface', 'region' : 'Surface', 'dofs' : {'Psi.0' : 0.0}, }
Which forces psi to be zero on the surface of Omega. Basically Dirichlet conditions. For acoustics the velocity potential needs to have no normal gradient at the surfaces.. more or less Neumann conditions. Is there an easy way to implement that?
What is the exact definition of the velocity potential? If it's really a Neumann-like boundary integral, having it zero = omitting the term in equations + no Dirichlet boundary conditions (ebcs) at all.
r.