To modify the 30x30x30 default grid applied to the CFD domain
proceed as follows. 

In file src/include/cfd.h set parameters NTCELX, NTCELY 
and NTCELZ to the number + 2. Due to user interface issues,
it is best not to exceed 99 in any direction. Then set
parameter MCEL1D to the largest assigned to the three
preceding parameters.

Note that the required RAM will grow linearly with the
number of control volumes (i.e. NTCELX*NTCELY*NTCEZ).

Reinstall bps, dfs and dfs by issuing the following
command from the ESP-r src directory.

         ./Install incl dfs bps prj 

Then do a 'make clean' in directories src/ebps, src/edfs
and src/eprj.

Where the number of control volumes is large, it is
useful to make dfs with compiler optimisation activated.
This is done by adding an option to the FFLAGS directive
in file src/edfs/Makefile: e.g $(MFC) $(FFLAGS) -c -O $<