Hello, Thank you for your e-mail. Based on the session file you have provided, you'll need to define the IO_FlowSteps parameter, given as <PARAMETERS> ... <P> IO_FlowSteps = 1000 </P> ... </PARAMETERS> Which would dump a .prs file that measures dp/dx (alpha) at every 1000 time-steps necessary to maintain the flowrate prescribed. For more information you could refer to the user-guide 11.10 https://doc.nektar.info/userguide/latest/user-guidese55.html#x76-36100011.10 Cheers, Chi Hin ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of 小已 <z2831727149@163.com> Sent: 04 November 2024 03:04 To: nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Failed to calculate the z-direction force in pipe flow This email from z2831727149@163.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. Dear Nektar++ developers and users I am a phd student from BIT(Beijing institute of technology), and I am using nektar++ to simulat turbulent pipe flow recently. my simulation is a 3DH1D.The mesh is a circular. The flow direction is z-direction and expand with Fourier transform.The caculation only outputs the forces in the x and y directions and the moment of the z-direction. However,I want to get the force in the z-direction on the wall and the program is unable to output. Is there any methods to solve it? The mesh and parameter files are attached. [https://count.mail.163.com/beacon/webmail.gif?type=webmail_mailtrace&guid=pr...]