mbkuhn
commented
1 month ago The reg tests have been updated to reflect this new usage of CFL for multiphase cases. These changes will only affect the reg test results in multiphase cases with a variable dt. From among those run by ctest, this is only the inertial_drop case, and I have confirmed that this is the only one that changes.
Summary
Multiplies advective CFL by 2 near interface so that different constraints, in different parts of the domain, can apply together.
Pull request type
Please check the type of change introduced:
Checklist
The following is included:
This PR was tested by running:
Additional background
The volume-of-fluid scheme implemented in AMR-Wind requires a CFL of < 0.5 to ensure conservation of each phase. Therefore, it has been the recommendation to run multiphase simulations at CFL < 0.5. However, for simulations where there are dynamics both near and far from the interface, such as an ABL simulation with waves, this may be unnecessarily restrictive, e.g., when the flow in the air is at a higher CFL compared to the flow near the waves. The changes in this PR multiply the advective CFL calculated near the interface by 2, so it can be compared with 1 instead of with 0.5. This will prevent dt from being overly restricted by the CFL in a multiphase ABL case.