Triangular 3rd order Lagrange elements have been implemented previously to study the numerical error associated with grid misalignment. It has previously been found that grid misalignment strongly affects numerical accuracy in the case of linear elements. The same conclusion was obtained by higher order finite difference. Here we observe that this is also true for higher order finite elements, up to 3rd order, when the solution has a steep gradient. Three types of meshes are considered. Type t1 has one element edge fully aligned with the strong transport direction; type t2 doesn't have any alignment with that direction; type t0 is a combination of t1 and t2, i.e., partial alignment.
展开▼
