On Thu, 10 Jul 2014, Sahai, Amal wrote: > 1) Compute momentum values (U*) at the new time step but without contribution > of the pressure terms. (Predictor) > 2) Update Pressure values using U* > 3) Correct new momentum values by taking into account Pressure values. > (Corrector) > 4) Update Energy equation. > > I wanted a little advice on how I should structure my solver to > ensure I make use of LibMesh's functionality. I would be solving a > Linear System in all the steps. Do I declare multiple Transient > Linear Systems each corresponding to the different steps in the > algorithm, and solve them one after the other for a given time step?
What you typically want is a TransientLinearSystem per set-of-variables. Say, one for (rho_u,rho_v,rho_w), another for (p), another for (rho_E). In this case you'd use the same system for steps 1 and 3, just with a state flag set to tell you to use a different assembly routine (or different terms in the same assembly routine) at the different stages. > Also, since the scheme is conditionally stable, I would need to > evaluate h/(c+|u|) at each node, where h would be the length of the > median from that node to the opposite side (unstructured). How can I > evaluate this? "opposite side" implies you're using triangles or tetrahedra alone? I recall (and Google confirmed) there being a simple formula for a triangle median's length: http://www.algebra.com/algebra/homework/word/geometry/The-length-of-a-median-of-a-triangle.lesson and I'd hope the formula with a tet is just as simple. Either way, you can get the length of a side with e.g. "(node1-node0).size()" --- Roy ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
