On Mon, Oct 20, 2014 at 3:31 PM, Xujun Zhao <[email protected]> wrote: > Hi all, > > For adaptive mesh refinement, an error estimator has to be used to > approximately evaluate the errors in each element in order to determine > which element is going to be refined. My question is which error estimator > should be used in the mixed FEM formulations, for example, Stokes equation > with u-p formulation. I read Bathe KJ's review paper: > A posteriori error estimation techniques in practical finite element > analysis, Computer & Structures 2005 p 235-265. > in which they suggested another local error indicator. > > I did try kelly and patch recovery, and they are useful to locate the > singular region and refine the mesh near the singularity. But the error > norms become larger and larger with the refinement. It seems that the > numerical solution is not convergent with mesh refinement.
Is your true solution (especially for pressure) in H1? If not, like for the non-leaky lid-driven cavity, then Kelly will keep giving you larger and larger error estimates. In practice, you can limit the amount of refinement in the singularity by calling max_h_level() on the MeshRefinement object. -- John ------------------------------------------------------------------------------ Comprehensive Server Monitoring with Site24x7. Monitor 10 servers for $9/Month. Get alerted through email, SMS, voice calls or mobile push notifications. Take corrective actions from your mobile device. http://p.sf.net/sfu/Zoho _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
