On Wed, 24 Apr 2013, Manav Bhatia wrote: > Has anyone attempted space varying dt for time stepping problems using > libMesh?
No, but we've got an application where it might be a decent idea. Half-ignorant rant: I'm skeptical, though. Space varying dt is ideal if you're doing a time-accurate solve of a hyperbolic problem, or if you can do operator-splitting and limit the space varying dt to the explicit operator(s) in a parabolic problem, but I've never seen how you can do implicit space-varying dt in a time-accurate way on parabolic problems without adding more DoFs to each space-time slab and so canceling out most of your benefits. What other implicit hypersonics people do with space-varying dt seems to be limiting it to non-time-accurate solves, where you're just pseudo time stepping to get to a quasi steady state. Which is fine, we do pseudo time stepping too... except that I think the right thing in this case may be to go coarser in time *and* space; if you're basically using the non-time-accurate parts of your solve just to get the shock moved into place so you can use larger dt, you might as well do most of that movement on a coarse grid. --- Roy ------------------------------------------------------------------------------ Try New Relic Now & We'll Send You this Cool Shirt New Relic is the only SaaS-based application performance monitoring service that delivers powerful full stack analytics. Optimize and monitor your browser, app, & servers with just a few lines of code. Try New Relic and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_apr _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
