When
checked, an improved narrow channel refinement strategy is effective
which ensures that narrow channels/passages are resolved by a sufficient number
of cells to predict the flow and heat transfer phenomena including
boundary layers with high accuracy. The default Maximum channel refinement level (Lch)
is set to the value which provides the number of cells across a
gap, no less than Ngap.
Otherwise, it depends on the Level of initial mesh (Lini)
and cannot be greater than four, resulting in the restriction of
the minimum size of cells across the model’s flow passage in the
normal-to-solid/fluid-interface directions. The consequence may
be a significant increase of the number of cells up to one or more
orders of magnitude.