Validation of Biglobal Floquet Analysis of Cylinder
******************* 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. ******************* Hello All ! I am trying to validate the Barkley JFM paper on the Biglobal floquet analysis of cylinder. I am doing the simulations at the following Re and Beta values to find the neutral modes and create a curve of neutral modes (as done in the paper) to identify the critical Re and Beta. 1. Re 190; Beta = 1.4 and 1.8. 2. Re 200, Beta = 1.2 and 2.0 For the above cases, the leading eigenvalue magnitude should be approximately 1. But the solver is producing eigenvalues with magnitude greater than 1. For example, converged eigenvalues for Re=190 and Beta=1.4 Magnitude Angle Growth Frequency EV: 0 1.28858 0.886868 0.202835 0.709494 EV: 1 1.28858 -0.886868 0.202835 -0.709494 EV: 2 1.13585 0.342226 0.101906 0.273781 EV: 3 1.13585 -0.342226 0.101906 -0.273781 For the base flow, I am doing DNS for around 40 shedding periods (~200s) and then storing 32 snapshots for the 41st shedding period. DNS solution is converged and validated against CD, and St values. The DNS mesh has around (~2050 Quads and 7th order polynomial). I also made sure that the 1st snapshot is not equal to the 32nd snapshot as mentioned in the user-guide. Later, I am interpolating the DNS snapshots to a coarser mesh (~550 Quads and 7th order polynomial) using FieldConvert. These interpolated chk files are used as baseflow for the Floquet Analysis. I would be highly grateful, if anyone could help me out with this. I have attached my case setup files for Re=190 and Beta=1.4 case. Case Files: https://drive.google.com/drive/folders/1-0fbs1mxAuQVKfYpbSpj5PBod2aQjKKS?usp... Thanks! Regards, *Gaurav Gupta* Scientist/Engineer-SC Space Applications Centre, ISRO Ahmedabad, GJ, India
Hi Gaurav, Please find the XML file which I used to validate Barkley & Henderson (1996) JFM paper for Re = 190, β = 1.6. Regards, Nandan Sarkar Postdoctoral Research Scholar Vanderbilt University From: "Gaurav Gupta" <gauravxpgupta@gmail.com> To: "nektar-users" <nektar-users@imperial.ac.uk> Sent: Wednesday, September 17, 2025 10:16:00 PM Subject: [Nektar-users] Validation of Biglobal Floquet Analysis of Cylinder This email from gauravxpgupta@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 [ https://spam.ic.ac.uk/SpamConsole/Senders.aspx | safe senders list ] to disable email stamping for this address. Hello All ! I am trying to validate the Barkley JFM paper on the Biglobal floquet analysis of cylinder. I am doing the simulations at the following Re and Beta values to find the neutral modes and create a curve of neutral modes (as done in the paper) to identify the critical Re and Beta. 1. Re 190; Beta = 1.4 and 1.8. 2. Re 200, Beta = 1.2 and 2.0 For the above cases, the leading eigenvalue magnitude should be approximately 1. But the solver is producing eigenvalues with magnitude greater than 1. For example, converged eigenvalues for Re=190 and Beta=1.4 Magnitude Angle Growth Frequency EV: 0 1.28858 0.886868 0.202835 0.709494 EV: 1 1.28858 -0.886868 0.202835 -0.709494 EV: 2 1.13585 0.342226 0.101906 0.273781 EV: 3 1.13585 -0.342226 0.101906 -0.273781 For the base flow, I am doing DNS for around 40 shedding periods (~200s) and then storing 32 snapshots for the 41st shedding period. DNS solution is converged and validated against CD, and St values. The DNS mesh has around (~2050 Quads and 7th order polynomial). I also made sure that the 1st snapshot is not equal to the 32nd snapshot as mentioned in the user-guide. Later, I am interpolating the DNS snapshots to a coarser mesh (~550 Quads and 7th order polynomial) using FieldConvert. These interpolated chk files are used as baseflow for the Floquet Analysis. I would be highly grateful, if anyone could help me out with this. I have attached my case setup files for Re=190 and Beta=1.4 case. Case Files: [ https://drive.google.com/drive/folders/1-0fbs1mxAuQVKfYpbSpj5PBod2aQjKKS?usp... | https://drive.google.com/drive/folders/1-0fbs1mxAuQVKfYpbSpj5PBod2aQjKKS?usp... ] Thanks! Regards, Gaurav Gupta Scientist/Engineer-SC Space Applications Centre, ISRO Ahmedabad, GJ, India _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
participants (2)
-
Gaurav Gupta
-
Nandan Sarkar