root = c25d-flo-inv-usm3d-[100*spacing]:

These purely-tetrahedral grids are in full scale meters and are
intended for 0 deg angle of attack, Mach 1.60, and have a uniformly
refined spacing in three dimensions of 0.64, 0.80, 1.00, 1.25, 1.56,
and 2.0. See the README two levels up for details. They were converted
from tetrahedra with the ugrid2tet (Ed Parlette) utility by
Mike.Park@NASA.gov

The grid files contain 83 boundary patches:
- patch 2 is inflow
- patch 4 is outflow
- patches 1,3,5-21 are the outer boundaries of the N-gon
- patch 22 is y-symmetry
- patches 23-83 are the aircraft outer mold line

[root].bc

formatted ASCII boundary triangles

[root].cogsg

real*8 data big endian FORTRAN unformated

[root].mapbc

USM3D boundary conditions
http://tetruss.larc.nasa.gov/usm3d/boundary-conditions/