Hi,
Can I ask if you were using the 2.5D instability ( a Fourier mode in the span wise direction) or the 2D instability. We did have an issue with the 2.5D code which has recently been fixed and I think is part of the current Master on the repository (*Chris* can you confirm if this is true). Can I first check you are using the most recent version of Master?
I think I used the 2D case. The config is the one found in Tests/ChanStability.xml (it is 2D right?). I actually left it ruining for 2 days on a cluster but it did not converge (with non zero initial vector) I pulled from git just yesterday.
Again can we find out which stationary solver you were running. Was this using the Selective frequency damping? If so perhaps Bastien can help check what might be going on here. Alternatively we tend to run base flows using the time marching methods until they get to a steady state. I was trying to use the SFD solver (both adaptive and classical). Are there any other stationary solvers? I have found an example in Tests/Cyl_AdaptiveSFD of how to set this up. Again if run with the initial flow, and eigenvector this works like a charm. But if I run it from scratch I have problems with convergence. (All I do is replace the InitialConditions).
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 have just run the ChanStability-Base.xml case and get an error of
L 2 error (variable u) : 0.00187368 L inf error (variable u) : 0.000533519 L 2 error (variable v) : 1.21301e-11 L inf error (variable v) : 6.97233e-10 L 2 error (variable p) : 6.41086e-10 L inf error (variable p) : 2.31381e-10
which does not seem correct. Is this also the answer you observe (note I only ran it for 2000 steps).
I am getting similar result. If I visualize it with ParaView it does not look as expected. I thing there is a problem with the Forcing, and the use or Periodic BCs. Is it not a problem to applay periodic conditions on pressure, without specifying a body force (pressure gradient)? Regarding the Periodic BCs, are you aware if it is possible to apply a fixed mass flux (I looked through the code and I think it is not, but if it is, please correct me). Best regards, Stanisław Gepner