******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hi Nektar++ community, I recently have been having issues using the stability analysis adjoint module. When running direct and adjoint stability analysis I would expect similar eigenvalues to converge. This is seen in the tutorial for ‘Global Stability Analysis: Cylinder Flow’. [image: image.png][image: image.png] Where the magnitude, frequency, and growth rate results are quite similar in value for the adjoint and direct Evolution Operators. However, from my own mesh and simulation of flow past a cylinder I get a discrepancy in the modes between direct and adjoint stability. Direct: [image: image.png] Adjoint: [image: image.png] My direct stability analysis simulation gives reasonable results; agreeing with the results in the Nektar++ tutorial on direct stability of a cylinder. But the adjoint stability modes are fairly different and don't yield values close to the tutorial. I have attached my case files for direct and adjoint stability. I would appreciate some insight if anyone has an idea why I have this discrepancy between direct and adjoint stability results. Thank you, Matt Duran PhD student University of Central Florida
Dear Matt There was an issue with the outflow boundary condition of your session file. It should be Robin boundary condition. Also, it is better to initialise your calculation with noise. I have updated your session file. With regards Abhishek --------------------------------------------------------------------------------------- Abhishek Kumar Assistant Professor (Research) Centre for Fluid and Complex Systems Coventry University, Coventry CV15FB, UK Web: https://sites.google.com/view/abhishekkir --------------------------------------------------------------------------------------- On Fri, Feb 11, 2022 at 2:18 AM Matt Duran <matt.duran60@gmail.com> wrote:
This email from matt.duran60@gmail.com originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list <https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address.
Hi Nektar++ community,
I recently have been having issues using the stability analysis adjoint module.
When running direct and adjoint stability analysis I would expect similar eigenvalues to converge. This is seen in the tutorial for ‘Global Stability Analysis: Cylinder Flow’.
[image: image.png][image: image.png]
Where the magnitude, frequency, and growth rate results are quite similar in value for the adjoint and direct Evolution Operators.
However, from my own mesh and simulation of flow past a cylinder I get a discrepancy in the modes between direct and adjoint stability.
Direct: [image: image.png]
Adjoint: [image: image.png]
My direct stability analysis simulation gives reasonable results; agreeing with the results in the Nektar++ tutorial on direct stability of a cylinder. But the adjoint stability modes are fairly different and don't yield values close to the tutorial.
I have attached my case files for direct and adjoint stability. I would appreciate some insight if anyone has an idea why I have this discrepancy between direct and adjoint stability results.
Thank you,
Matt Duran
PhD student
University of Central Florida _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
--
participants (2)
-
Abhishek Kumar
-
Matt Duran