Criterion of momentum equation convergence
In a way
that is quite similar to the energy equation, the residual error
(rkmom)
for the momentum equation is defined as follows:
 | (1) |
|---|
where the residual error for i-th component of momentum at the control volume (“cv”) is:
 | (2) |
|---|
Here:
 | (3) |
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where:
 | (4) |
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where the member 
contains
approximations of other terms including a pressure gradient and
forces.
The reference residual value
(
) is defined as:
 | (5) |
|---|
where:
 | (6) |
|---|
Thus, 
is
treated as the reference value of the momentum flux (jmom,cv)
through the control volume. Finally, the convergence condition for
the momentum equation is:
 | (7) |
|---|
and the stopping criteria Equation 7 can be treated as:
 | (8) |
|---|