Dear Roger, I see several possible reasons for deterioration of the pressure at the center line.
First, you are integrating singular functions. Have you adapted the quadrature rule? Second, boundary conditions at the center line. I am not sure what is optimal there, and there might be different options. Third, the quadrature weights converge to zero at the center line. It might just be, that you cannot obtain a good pressure solution there. I hope this helps, Guido On Sat, Jun 30, 2012 at 9:38 PM, Roger Rennan Fu <[email protected]> wrote: > Hello all, > > I'm trying to model viscous flow due to self-gravity in the interior of a > partially molten asteroid, which existed in the early solar system. I'm > using an altered version of step-22, and everything works fine until I try to > use an axisymmetric domain- specifically, a 2-D domain representing a solid > of rotation around the y axis. > > Somehow, the pressure solution shows anomalies near r=0 and the div(u) = 0 > condition is not well-satisfied. I think I have altered the system setup > properly, modifying the divergence and the integration to reflect cylindrical > coordinates, but something is still not right! Have other people had > experience in implementing the Stokes equations in axisymmetric coordinates? > Is there an example somewhere you can point me to? > > Thanks for any and all help! > Roger > > _______________________________________________ > dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii -- Guido Kanschat, Department of Mathematics, Texas A&M University In accordance with the Texas Public Information Act all email sent to and from my Texas A&M email account can be obtained through a Public Information Request. If you do not want your correspondence public, please arrange a phone conversation with me. _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
