> I have tried a simple testcase for my problem. >> I don't know if it's suitable as a testcase but if I use X=0 in my >> equations above, I know the solution. >> >> The solutions is u = v = 0, \phi = (1-x^2 -y^2) and the pressure is then >> P = 8 \phi_lin^2 (1-x²-y²) >> It fits with my boundary conditions which are u = v = p = \phi = 0 at the >> boundaries. >> >> Here are the results for dealii with a = 2 and phi_lin = 4*pi. >> Left is the L2 norm of u and v. As you can see it's going to 0 when i >> jump to a higher refinement cycle. >> > > Is the rate of convergence as expected? >
I believe so. I did a linear regression of the convergence graphs in logscale and got a value of : -7.6 for the speed : I believe it corresponds to the -8 from second order finete element in 2D -3.2 for the pressure : I beliebe it corresponds to the -4 from the first order finite element in 2D > > >> I'm a bit at a lose. Why does it work for X = 0 but not when I use a >> different X ? >> > > Are you sure that your deal.II solution is wrong in fact? > I'm not sure at all if this solution is wrong or not. I have to admit this solution looks very good to me and suits the results I was hoping for. It's just different from the one given from another code (the mathematica one) and I don't understand why. It could be the other code that gives a bad solution. > If u = v = 0 in your test case, there might still be a problem with these > equations. > I'm not sur to understand what you are saying here. Can you elaborate why you think there is a problem in my equations ? > I would also try a case where you manufacture a solution and implement a > right-hand side term such that this is the solution to your equations. > I'm trying this at the moment Since the ansatz space on non-affine mapped geometries is not polynomial > anymore, I would also try a cartesian mesh for the case that the solution > is contained > in your ansatz space. > I don't really understand what you mean by ansatz space although I have looked it up on google. Do you suggest that I try the X=0 solution on a square mesh ? Thanks again for your help, this is really helpful to talk about this to someone. > > Best, > Daniel > > -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/b595db11-0478-449d-9c80-2b686c179e39%40googlegroups.com.
