mesh
  radial trisection
  trisection blocks, 2
  zmin -0.00075
  numz 1
   zblock 1 1. interval 4
  numr 3 
   rblock 1 2.0 interval 4
   rblock 2 3.0 interval 4
   rblock 3 4.0 interval 4
  numa 1
   ablock 1 90. interval 12
 end
 set assign
  nodeset, ilo, 100
  block sideset, ihi, 45, 2
 end
end
