From: Michael Povolotskyi <povolotskyi@in...>  20050217 11:21:29

Dear Libmesh developers, with your help we are getting some progress. As you have suggested we tried linear elements (Tri3 and Quad4). In this case the countour lines look continuous everywhere. However, we still see some differences between Tri3 and Quad4 elements. The solution with Quad4 looks very nicely. The solution with Tri3 has some problems. Namely, there are several nodes that lie at the boundary with the boundary condition u = 0.0 whose value depends on the adaptive grid refinement. Without refinement the value is equal to 0.0, as it should be. Then we did 5 adaptive refinements and the values were: 0.004 1e15 1e15 1e27 0.001 . The futher refinements lead to a constant value at these nodes of about 0.002. The value of about 0.001 seems to be too much for the numerical error. Thank you very much, we hope that our feedback is usefull. Michael. 