convert a binary flowfield to HDF5 file format.

  -p           --padding               save full Nx x Ny x Nz grid rather eliminating padding
  <fieldname>  (trailing arg 2)        flowfield input file
  <hdf5file>   (trailing arg 1)        hdf5 output file

   field2hdf5 u.ff u.h5

You can drop the file extensions if you like.

The HDF5 file contains

• the components of the field in the group /data
• the values of Nx, Ny, Nz, Lx, a, and b as attributes of the root group
• the gridpoint coordinates x,y,z in the group /geom