I have been trying to use Selective frequency damping (SFD) method adopted in the SteadyState Driver, in order to get an unstable steady state solution whose stability is to be determined. I see in the nektar++ user guide there are two approaches: classical one, and the adaptedSFD. I am trying to validate the case of flow past circular cylinder at Re=100 studied by Jordi link herein

https://spiral.imperial.ac.uk/bitstream/10044/1/31875/.../Jordi-B-2016-PhD-Thesis.pdf . With the values of growth rate and frequency mentioned in this thesis, i am able to achieve convergence upto O(-8) for the classical approach.

The problem arises when I use AdaptedSFD method. Initially, AdaptedSFD runs smoothly untill tolerance O(-2), then it switches to stability analysis to estimate growth rate and frequency which is used to predict next value of control coefficient and filter width. The problem lies in the estimation of growth rate and frequency which give nonphysical large values of order 10. I have attached the Session.xml, Session_LinNS.xml, and output results generated. Any help is highly appreciated.