HI, I think we have used the Acoustic solver previously using an incompressible bae flow. I guess it is possible with the compressible code but not sure we have tried it previously. Regarding the lamb vector you need to calculate the vorticity then can probably use Fieldconvert option fieldfromstring module to calculate the lamb vector with the functionality of the form: FieldConvert -m fieldfromstring:fieldstr="x+y+u":fieldname="result" file1.xml file2.fld file3.fld I do not think the lamb vector is zero in 2D. Best, Spencer. From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Gao <feigao2024@126.com> Date: Tuesday, 5 November 2024 at 09:43 To: nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Get source from CFD This email from feigao2024@126.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. Hello, I want to simulate the 2D cylinder in a crossflow in CAA. First, I need to compute the cylinder case by Compressible solver, then use the result of Compressible solver as the source of Acoustic solver. But how can I get the Lamb vector in CFD simulation? I think the Lamb vector in 2D is zero, am I right？ Could someone give me some advice? With best regards