Vatslav, you will have to use the neknek script that allows you to exchange data between two Nek5000 sessions that are run simultaneously. You should have a look at the neknek examples to understand how to set up your usr file. Some of the subroutines that will be useful to you are located in the following link: http://www.mcs.anl.gov/research/projects/nek5/docs/html/multimesh_8f_source.... You will have to modify some of them to fit your needs since for example the subroutine ‘set_inflag’ is written to look for ‘in’ boundary conditions and replace them with ‘v ’. You will need a subroutine that looks for ‘in’ and substitute it with either ‘v ‘ or ‘P ‘ depending on the which pipe you are at. Marco On Mar 24, 2017, at 4:16 AM, [email protected]<mailto:[email protected]> wrote: Hi, Neks! I have two pipes in my simulation. They are placed near each other on one axis with empty space between. One of them with periodic boundary conditions on z direction, another one - inflow -> outflow. How can I copy velocity slice from one of boundary on first pipe with periodic bc to the inflow boundary on second pipe? Regards, Vatslav. _______________________________________________ Nek5000-users mailing list [email protected]<mailto:[email protected]> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users