Hi, The problem is that I have to solve my equation on the same domain with very different boundary conditions, making a uniform refinement very inefficient and a waste of time, and worse in my case, RAM. So I do need to start with a very course mesh and refine.
cheers Joa On Tue, Oct 13, 2009 at 09:55:54AM -0400, David Knezevic wrote: > If you generate a mesh in gmsh that is sufficiently fine that a mesh > of second order elements captures the geometry well enough, then you > can read that mesh into libMesh, and just use libMesh's adaptive > refinement as in the examples. In that situation, libMesh's adaptive > refinement will interpolate the quadratic boundaries when you refine > the boundary elements... > > But if you want to start with a very coarse mesh, then you might > have to move boundary nodes around etc. I've never had to do that > myself, so perhaps someone else on the list can offer you some > choice advice. > > - Dave > > > Joa Ljungvall wrote: > >Hi, > > > >I'm not sure I understood the answer. I want to start with a very > >course mesh, and refine it based on the solution on the course(r) > >mesh, i.e. adaptive > >refinment. So using gmsh I would have to communicate the solution > >in each step and tell gmsh which regions to refine, or? And if so, > >how? Further more, my domain have some regions where a cylinder it > >cut by a hexagonal, so a quadratic approximation would not do so > >well, would it? > > > > > >cheers > > > > > >Joa > > > >On Tue, Oct 13, 2009 at 09:24:53AM -0400, David Knezevic wrote: > >>I think the simplest thing to do is use second order elements in gmsh. Then > >>when you refine the new nodes will interpolate the quadratic > >>approximation to > >>the boundary of your domain. > >> > >>- Dave > >> > >> > >> > >>Joa Ljungvall wrote: > >>>Hi all, > >>> > >>>I would like to use libmesh to solve a rather simple equation > >>>(Laplace/poisson) > >>>but in a domain with a somewhat funny shape of the boundary. To do > >>>this I created a mesh using gmsh, modified example 14 a bit so it > >>>reads my mesh > >>>instead of the l-shaped domain. My problem is that when I refine I get > >>>"flat" > >>>surfaces that does not follow my boundary (which is not flat;). How do I go > >>>about and move the new boundary vertices of my tets (I use tets) to the > >>>real > >>>boundary? As for the geometry etc. I now how to do it, I`m just not so > >>>familiar > >>>with libmesh. > >>> > >>> > >>>kind regards > >>> > >>>Joa Ljungvall > >>> > >>> > >>>------------------------------------------------------------------------------ > >>>Come build with us! The BlackBerry(R) Developer Conference in SF, CA > >>>is the only developer event you need to attend this year. Jumpstart your > >>>developing skills, take BlackBerry mobile applications to market > >>>and stay ahead of the curve. Join us from November 9 - 12, 2009. > >>>Register now! > >>>http://p.sf.net/sfu/devconference > >>>_______________________________________________ > >>>Libmesh-users mailing list > >>>[email protected] > >>>https://lists.sourceforge.net/lists/listinfo/libmesh-users ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
