On Wed, 5 Dec 2012, ernestol wrote: > I will try to set the nodal value directly, thank you.
This *still* won't give you a ringing-free solution. Imagine you're trying to interpolate a step function which changes from 0 to 1 less than halfway through a 3-node quadratic line element. You'll set the first node to 0, the second node to 1, and the third to 1, and the quadratic function will peak 3/4 of the way through the element with a value of 9/8, greater than 1. What's more, didn't you say you're doing Cahn-Hilliard with the typical polynomial free energy functional with a trough at 1? In that case even the *true solution* can temporarily exceed 1, IIRC - the local free energy term penalizes but doesn't forbid such excess, and in the transient case the local term can be temporarily dominated by the interfacial free energy effects. If you're coupling Cahn-Hilliard to another equation that NaNs or goes unstable or whatever when it sees c>1, you'll need to either truncate c in the coupling or use something like a Flory-Huggins free energy that really does prevent c>1 solutions. --- Roy ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
