The integration splitting implemented in commit a5806207 has been shown
to be incorrect in some cases. A new procedure has been implemented
which can correctly split the implicit-explicit integral into a number
of pieces, in order to calculate the contribution of each. This is
intended for integrating coupled and non-coupled particle momentum and
heat transfers.
However, currently there is only ever one implicit coefficient used in
these transfers (there is no implicit non-coupled contribution). The
evaluation has therefore been short-cutted to only do the integration
with respect to the coupled contributions. The splitting functionality
has been retained in case additional separate implicit coefficients are
required in the future.
This change was made with help from Timo Niemi, VTT
This resolves bug report https://bugs.openfoam.org/view.php?id=2666
9ee3bbc943