Dear Neks, I'm simulating the flow in a 90 degree bent pipe. I am trying to build a non-uniform mesh which is finer in the bent section and coarser in the straight sections. For this purpose I am writing this code in the subroutine usrdat2: do i = 1, nelv iel=lglel(i) if (iel.le.960) then z = 0.8*z elseif ((iel.gt.960).and.(iel.le.1728)) then z = 3.*z elseif (iel.gt.1728) then z = 0.5*z endif enddo The idea is to dilate the coordinates in the straight sections and to shrink them in the bent section so that the mesh would be non-uniform. However, this doesn't work. Is this the correct procedure? Thanks. Best regards.