The diffusion term amounts to
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(605) |
which amounts to, taking into account Equations (591) and (592):
where
is the total dynamic viscosity. The first term contains the gradient in normal direction. For face e between
elements P and E it is approximated by:
This amounts to the following approximation:
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(608) |
This amounts to a deferred correction for the gradient. Terms 2 and 3 of
Equation (606) are computed from iteration :
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(609) |
The boundary conditions for the diffusion term deserve special attention. The following cases are distinguished: