HI Ali, Have you tried setting “awgn(sigma)” in the boundary condition string. To make a boundary condition time dependent you then need to add the string “USERDEFINED=“TimeDependent”. Cheres, Spencer On 29 Jul 2019, at 20:21, Akhavan Safaei, Ali <akhavans@msu.edu<mailto:akhavans@msu.edu>> wrote: Hello everyone, I need to generate a velocity boundary condition for IncNavierStokesSolver as a Gaussian random process (in time) in the session file. I know we can use "awgn(sigma)", for example, to generate Gaussain random I.C.; but, I haven't been able to fine a way to extend it to random process B.C. . I would greatly appreciate it if anyone can help me with that. Best, Ali Akhavan-Safaei ---------------------------------------------------------------------------------- Ali Akhavan Safaei, PhD student, Graduate Research Assistant Michigan State University Department of Mechanical Engineering 428 S. Shaw Lane Engineering Bldg., Rm. #4110 East Lansing, MI 48824 Email: akhavans@msu.edu<mailto:akhavans@msu.edu> akhavans@egr.msu.edu<mailto:akhavans@egr.msu.edu> ---------------------------------------------------------------------------------- _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users Spencer Sherwin FREng, FRAeS Head, Aerodynamics, Director of Research Computing Service, Professor of Computational Fluid Mechanics, Department of Aeronautics, s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> South Kensington Campus, Phone: +44 (0)20 7594 5052 Imperial College London, Fax: +44 (0)20 7594 1974 London, SW7 2AZ, UK http://www.imperial.ac.uk/people/s.sherwin/