In userf you specify the forcing for the flow (i.e. Navier-Stokes equation) and in userq the source for the energy. In case you have additional passive scalars you can distinguish between them via the variable 'ifield'. For more info see the online documentation. oana ________________________________________ From: [email protected] [[email protected]] on behalf of [email protected] [[email protected]] Sent: Thursday, January 21, 2016 11:33 PM To: [email protected] Subject: [Nek5000-users] Need for clarification on the SOURCE TERM Dear Sir, How to find out whether the source term which I wish to incorporate in the Navier Stokes equation, will be added to the momentum or energy equation. Thanks & Regards Prashanth Mohanasundaram