Hi Gong, We have applied the transient growth to non periodic base flows by interpolating snapshots. I am cc’ing Ankang who can confirm if the interpolation feature is in the master branch or a separate branch currently. Since we use an explicit in time discretisation for the advection term which will depend on the same base flow as the forward problem I suspect you will need a similar CFL condition. I have however not investigated this. Cheers, Spencer. On 16 Jul 2021, at 03:40, gongminjiang@hrbeu.edu.cn<mailto:gongminjiang@hrbeu.edu.cn> wrote: This email from gongminjiang@hrbeu.edu.cn<mailto:gongminjiang@hrbeu.edu.cn> 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 Sir or Madam, I have two questions when using transient analysis: 1. The transient growth analysis in Nektar++ is only useful for steady or periodic base flow, right? 2. The CFL when processing the backward equation maybe much large. Is it OK for linearised operator? Regards Gong _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users