Hello Wolfgang, What you mention at the beginning is correct, that's exactly what I would like to do. Mathematically I would do the following:
1) Use the cell quadrature points to reconstruct a finite element function defined on the cell. 2) Take the trace of this function along the boundary face. 3) Evaluate it at face quadrature points. Any thoughts on how to implement this? Javier On Friday, February 23, 2024 at 2:44:15 AM UTC-8 Wolfgang Bangerth wrote: > On 2/21/24 15:10, Javier Almonacid wrote: > > > > Is there any method already implemented in deal.II to project cell-based > > quadrature point data onto the boundary? The end goal is to compute some > > forces on the surface in step-44 and for that, I need to project the > Kirchhoff > > stresses (tau) onto the boundary. > > > > An idea that occurred to me was to first project the quadrature point > data > > into a more global element with DOFs (a finite element function) using > one of > > the recommended extensions in step-18. However, I don't know if this is > a good > > start because then the problem is how to project this object (coming > from say, > > FE_DGQ) onto the boundary (these are all cell-wise operations by the > way, as > > in step-18). > > Javier, > do I understand correctly that you have some quantity (in your case the > Kirchhoff stress) stored at quadrature points of each cell only, and you > wonder how you could get an approximation of that quantity at points on > the > faces of that cell? > > I can think of a number of ways of doing this, including interpolating or > projecting onto a finite element field and evaluating it, but also just > taking > the cell-q_point that is closest to the face-q_point. In the end, can I > ask > you for a concise mathematical definition of what you want to do first, > and > then one can think of how to implement it? > > Best > W. > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@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/0810ef39-cf40-4d13-af60-cf8a080f5e5fn%40googlegroups.com.
