******************* 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. ******************* Dear all, I am studying 2D linear stability analysis. I have browsed through the emails of the nektar community and learned a lot about solving settings, but there are still some questions that I cannot understand. Everyone can offer their opinions. 1. Is the combination of fine mesh and low order unfolding more effective? Is it better for the order of pressure 'p' to be 1 order lower than the velocity 'u, v'? 2. When using Arpack for serial computing, will setting kdim to a larger value result in faster solving speed, such as 64 and 128? Because I encountered incorrect eigenvalues in my calculations, such as an unstable flow with a growth rate less than 0. Do I need to set the nvc to a large value? 3. The post mentioned that using smooth initial conditions can avoid calculating eigenvalues as 1. How should I set it up? Can you provide a specific example? 4. How should base flow be calculated? Should I average the extraction time of DNS results or use the SFD method? How to set the parameters in the adaptive SFD method to ensure both solution convergence and fast computation speed? The direct.xml and SFD.xml files are attached.Thank you for your suggestions. Qiancheng