Dear Sirs,
First of all thank you for developing this great software and making it
available.
I am planing to investigate stability of an incompressible channel flow
using Nektar.
I have studied the manual and the source (the version from the git repo)
and repeated some of the examples
from the IncNavierStokesSolver folders Tests and Examples.
The channel flow stability test (Tests/ChanStability.xml) uses a base
flow (.bse) and an initial guess (.rst) and converges to an expected
result. Now, as practice I tried to play around with the settings, first
by changing the Driver to Arpack (this works as well).
Since I might not know the initial approximation I tried to get rid of
the initial guess, and replaceed it with some random initial vector (I
have put zeros, non zeros, the awgn()). This time the problem did not
coverage at all (I increased the numbers of iterations, tried to modify
the number and size of the time steps, change the dimension of the
Krylov space).
Is this an expected behaviour? And since this is a test, the problem is
set up to be small and quick and would only converge with the proper
initial vector? Should I expect a similar problem for a larger 3D case?
My second question concerns the base flow. I tried to recover the base
flow using the stationary solver (both classical and adaptive) but I
failed. Could you point me at an example of how to set this up?
Also I noticed (or I think I did) that the
Example/ChanStability-Base.xml does not produce a correct flow field. Am
I right?
I would appreciate if you would comment on my questions.
Best Regards,
Stan Gepner