what's R-refinement and h-refinement?
 

plz explain them ,thanks.

ok,i have found the answer:
In the first, h-refinement, increased local resolution
of solution features is accomplished by recursively subdividing mesh cells where needed. This
technique is used by both the Cartesian grid and the unstructured grid communities. In the second category,
r-refinement, the number of mesh nodes and cells remains constant, but nodes are relocated to areas where
needed to increase resolution. It can be argued that each type of re®nement will produce acceptable resolution
improvement under appropriate usage.