Clipped outflow made default for momentum equation

[mbkuhn]

Summary

This change should have been in #1287, but it was missed. Because of that, inflow at outflow was still automatically allowed in the momentum equation (ICNS). This removes that; changing the default to a clipped outflow (clipping velocities going into the domain)

Pull request type

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Checklist

The following is included:

• new unit-test(s)
• new regression test(s)
• documentation for new capability

This PR was tested by running:

• the unit tests
  • on GPU
  • on CPU
• the regression tests
  • on GPU
  • on CPU

Additional background

This should actually cause the diffs I expected in the other PR...

[mbkuhn]

won't merge until feedback on issue #1341

[mbkuhn]

@marchdf would you say the CI is acting up again? see the CPU fails

[marchdf]

yeah this kind of thing:what(): UtilCreateCleanDirectory:: std::rename failed makes me thing there's something up with the CI filesystem. Let's see if it clears up. I wouldn't worry unless this keeps up

[mbkuhn]

At the moment, issue #1341 appears to be caused by something else, and it is more setup-related. This PR doesn't fix that problem, but this PR needed to go in either way.