Add sliding mesh capability

Issue/feature addressed

Implement the ALE method for sliding mesh with rotating, sliding, and prescribed motions in ADRSolver and CompressibleFlowSolver.

Proposed solution

• Nektar::SolverUtils::ALEHelper was added to implement the ALE method.
• New class members m_gridVelocity and m_gridVelocityTrace were introduced.
• Add a flag m_ALESolver for the ALE method.

Implementation

In order to introduce grid velocity, the function ALEHelper::InitObject was utilized to initialize the variables m_gridVelocity and m_gridVelocityTrace. As the mass matrix undergoes changes during the ALE process, the function ALEHelper::ALEPreMultiplyMass is employed to perform mass matrix multiplication. ALEHelper::ALEDoElmtInvMass and ALEHelper::ALEDoElmtInvMassBwdTrans were used to attain the variables in coefficient and physical space, respectively. To perform movement, ALEHelper::MoveMesh was used to call Movement::PerformMovement.

Tests

In ADRSolver

• Movement_rotate_3D_stacked_cylinders_curved_par
• Movement_translate_interfaces232_dirichlet

In CompressibleFlowSolver

• Movement_rotate_couette

Suggested reviewers

Chris, David

Notes

• There are issues with ALEHelper::InitObject called in SolverUtils::UnsteadySystem when using CG projection and the pulse wave solver. There needs to be a redesign to address this problem.
• Changes in SolverUtils::Advection::AdvectionWeakDG and CompressibleFlowSolver::Diffusion::DiffusionLDGNS to avoid implicit solver errors may also need to be redesigned.

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).