PSAAP3 WENO

Standalone Fortran WENO code with Loopy transformations.

Notes

• The WENO scheme is taken from [1]
• The Roe matrix implementation follows the internal PlasCom2 documentation
• Boundary conditions are not really handled correctly at all
• A declaration of "real" is not intended to suggest single precision
• This implementation does not include the severe shock correction proposed by [1]
• Current assumption for metrics is that metrics(i,j) = (\xi_i)_(x_j)
• It's not immediately obvious, but there might be some wasted work in the frozen generalized flux computation
• Right now the specific gas constant gamma is implemented as a magic number (1.4) -- this should be generalized

Fortran dialect wishlist

• Automatic line continuation in parentheses
• Array-valued expressions
• In-place operators
• Slicing that automatically picks an increment of -1 when appropriate
  • (e.g. 2:0 instead of 2:0:-1)
• Scalars with intent(out)

Note: Tag 'nice' references the code at a point where several of these items are used

Testing plan

Plan to test the following routines directly:

• compute_flux_derivatives
• convert_to_generalized
• convert_to_generalized_frozen
• convert_from_generalized
• roe_eigensystem
• pointwise_eigenvalues
• lax_wavespeeds
• split_characteristic_fluxes
• weno_flux
• consistent_part
• dissipation_part_pos
• dissipation_part_neg

References

[1] Nonomura, T., Terakado, D., Abe, Y., & Fujii, K. (2015). A new technique for freestream preservation of finite-difference WENO on curvilinear grid. Computers and Fluids, 107, 242–255.