Enable Simo/Dong-Advection for VCSImplicit

Issue/feature addressed

Enable two variants of the implicit Velocity-Correction Scheme (VCSImplicit). The scheme described in Simo and Armero, 1991 as well as the previously available scheme by Dong and Shen, 2010.

Proposed solution

Enable choosing the advection velocity \tilde{u} that approximates/linearises the advection operator as u^{n+1} \cdot \nabla u^{n+1} \approx \tilde{u} \cdot \nabla u^{n+1}.

Implementation

An additional SolverInfo parameter AdvectionVelocity can optionally be chosen as either Simo or Dong for the two schemes. The default option is the Simo scheme since it has shown better stability characteristics in 2D.

Tests

• The available tests for VCSImplicit have been adjusted to run with the Simo scheme
• A separate test for Dong-Advection has been added

Suggested reviewers

@mlahooti @dmoxey

Checklist

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