I have found my problem. A boundary condition in my mesh was ill-defined and this lead to my error. Sorry for the confusion. Thanks
On Monday, 19 February 2018 13:41:35 UTC-5, Bruno Blais wrote: > > Hello, > Sorry I feel I have not explained myself correctly. Here is a drawing of > the case: > > > <https://lh3.googleusercontent.com/-4py-EISXcqc/WosZebbKS-I/AAAAAAAAC5w/-qHRMSkwW6IinnVGocwlonnFHrF3rXXbQCLcBGAs/s1600/text4174-2.png> > > With Ux may be a profile or a constant. > Initially I had set-up that case with Ux as a Poiseuille flow profile and > the Top and Bottom as no slip boundary conditions. In that case I got the > solution I was expecting. Convergence was good and the solution was what I > had in mind. > Then what I wish to do is set Ux as a constant and apply slip at the top > and bottom boundary conditions. When I do this is when I am unable to reach > convergence in my iterative solution, yet I do not understand why because > the problem should be well posed. > I don't think that leaving my right boundary as a free traction boundary > condition is problematic since it is by all mean an outlet boundary. This > worked well for instance in a backward facing step case. > Thank you for your time, sorry for the confusion. > Best regards > > > > On Monday, 19 February 2018 10:50:48 UTC-5, Timo Heister wrote: >> >> > Does the order in which I apply the nonzero and zero constraints >> matter? >> >> These are two independent objects, so no. >> >> > Currently I apply the inlet and then the no-slip in the >> nonzero_constraints, >> > thus the bottom and top wall appear after the inlet. Afterward the >> cylinder >> > is put in the zero constraints. >> >> I don't understand. You need boundary conditions in >> nonzero_constraints and zero_constraints for all boundaries. The >> reason for these two sets is that one is used for the initial solve, >> while the second one is used for the Newton updates. >> >> >> -- >> Timo Heister >> http://www.math.clemson.edu/~heister/ >> > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
