Draft: Add a new feature of partial slip boundary condition

Issue/feature addressed

Generally, the no-slip condition should be satisfied on the solid wall. For hydrophobic materials, however, partial slip on the wall is allowed. This merge request added an implementation of a partial slip boundary condition with a constant slip length.

This merge request is also a preparation for the wall model branch !1266 (closed)

Proposed solution

The partial-slipe model is set as a Dirichlet-type boundary condition, where the boundary velocity equals the multiplication of the slip length and wall-normal velocity gradient. The slip length is specified in the boundary condition.

Implementation

A new calss SlipWallBoundaryCondition is created to evaluate the slip velocity. A relaxation iteration is added in the function VelocityCorrectionScheme::v_SolveViscous to enforce the partial-slip boundary condition.

Tests

Notes

Please add any other information that could be useful for reviewers.

Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Newly added files are correctly formatted.
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).