On 1/14/20 10:04 PM, David Eaton wrote: > > Thank you for your suggestions. I am going to take a look at Lethe and > compare > with my implementation. In stabilized formulation, I used quadrilateral > element, instead of P2 P1 Taylor-Hood element. The used element is only C0 > element. I also did not expect such a discontinuity between elements. > Although > I use P2 P1 Taylor-Hood element without stabilization terms, the > discontinuity > is still there. Probably I made mistakes somewhere in setup. I also suspect > that my solution is not converged. After taking a small relative tolerance > 1e-8, the discontinuity still appears.

David, you did not understand what we were saying: If you use C0 elements (think, piecewise linear) and you take derivatives to compute the vorticity, then you automatically get a discontinuous function. That has nothing to do with stabilization, solver tolerances, etc. It's just a consequence of the fact that C0 elements and their shape functions have kinks and consequently their derivatives are discontinuous. Best W. -- ------------------------------------------------------------------------ Wolfgang Bangerth email: bange...@colostate.edu www: http://www.math.colostate.edu/~bangerth/ -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/f03c64fc-3736-340a-1cdc-f24749fb413f%40colostate.edu.