Hi, John, Thank you for your helpful response.
Since the lid driven cavity problem is actually a steady problem, it seems that always the steady result will be obtained after the non-linear iteration, which also means we get the final result in the first time step. Is it right? Regards, Kai On Mon, Jan 30, 2012 at 12:27 AM, John Peterson <[email protected]> wrote: > On Sun, Jan 29, 2012 at 12:47 PM, Bao Kai <[email protected]> wrote: >> Hi, >> >> I am just starting to lean Libmesh. >> >> I have a question on ex13. I want to know what the Newton term means in >> ex13. > >> theta*dt*(U*grad_u)*phi[i][qp]); // Newton term > > The Newton method of Example 13 is atypical: rather than solving for > the "update" du_{k+1} = u_{k+1} - u_{k}, it solves for u_{k+1} > directly. > > So the "standard" Newton iteration: > > J_{k} du_{k+1} = -F_{k} > > is instead written as: > > J_{k} u_{k+1} = -F_{k} + J_{k} u_{k} > > This modified RHS can be computed by hand; it involves the term you > asked about above. > > -- > John ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
