Encyclopaedia Index
Nett-source print-out in
RESULT
The RESULT file contains, below the print-out of the solved and stored
variables, a tabulation of the "nett sources" of all the
patches
which have been used to create sources or boundary conditions.
These nett sources are the sums, for all cells in the patch, of:
CO * ( VAL - VAR ) * "type multiplier"
where:
- CO and VAL are the coefficient and value
appropriate to the cell and variable, as specified by the
COVAL
command in the Q1 file;
- VAR is the value of the solved-for variable in the cell,
and
- "type multiplier is unity, or cell volume, or area, etc,
according to the
type of the patch.
Moreover, the RESULT file also contains, for each solved-for variable:
- the summation of all the positive sources;
- the summations of all the negative sources; and
- the difference between them, which is to say the whole-domain nett source for the variable.
There are three exceptions, namely:
- nett sources which are equal to zero (perhaps because CO
has been set to zero, are not printed:
- sources are also not printed for those patches for which
CO has been set to FIXVAL;
- when CO has been set to a sufficiently large value that
VAL - VAR becomes so small in comparison with VAL
and/or VAR themselves that round-off error renders its value doubtful, the nett source is reported as 1.234 .
Then the user is advised to set CO to a smaller value.
Apart from the physical interest attaching to the nett sources, they also convey valuable information about the extent the which the
solution of the equations is adequately converged.