[Nek5000-users] Problems in getting eigenvalues using ARNOLDI

[nek5000-users at lists.mcs.anl.gov]

Hi Nek,
  I am running  ARNOLDI simulation case for a flow over a 2D cylinder using
ARPACK . My domain is [-50,50] and Re=50. I have calculated base flow using
SFD method. While calculating Eigen values I have to run the restart around
16-20 times to get an eigenvalues.txt file as an output.

Also the eigenvalues that are coming most of them has zero rotation i.e.,
they are negative real value. Suppose I want to have 30 eigenvalues as an
output and I am setting Krylov subspace as 90 then I am getting around 20
of eigenvalues having zero rotation.


Kindly help as I am stuck in it for long. Thanks in advance.

Regards,
 Alok Mishra

            Aerospace Department IIT Kanpur
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