[Syphonicc]

Proposed Changes

CNSSolver::BC_Isothermal_Wall_Generic calls GetCHTWallTemperature with dist_ij and thermal_conductivity swapped:

// declaration: (config, val_marker, iVertex, thermal_conductivity, dist_ij, There, Temperature_Ref)
Twall = GetCHTWallTemperature(config, val_marker, iVertex, dist_ij,
                              thermal_conductivity, There, Temperature_Ref);

Inside the function the fluid-side weight becomes HF_FactorHere = dist_ij * Viscosity_Ref / k instead of k * Viscosity_Ref / dist_ij, so the interface temperature computed by the AVERAGED_TEMPERATURE_NEUMANN_HEATFLUX and AVERAGED_TEMPERATURE_ROBIN_HEATFLUX couplings uses a wrong weighting between the fluid and solid sides. The incompressible solver (CIncNSSolver::BC_Wall_Generic) computes the same factor inline with the correct order. This PR swaps the two arguments back.

The DIRECT_* couplings (the default) do not use these arguments, so existing regression tests are unaffected.

Related Work

None.

PR Checklist

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

Testing

• cht_compressible (coupled_cht/comp_2d, default DIRECT_TEMPERATURE_ROBIN_HEATFLUX): bit-identical to the reference values.
• Same case with CHT_COUPLING_METHOD= AVERAGED_TEMPERATURE_NEUMANN_HEATFLUX, 2000 outer iterations, 4 ranks: the solution changes as expected (fluid-zone integrated heat flux -34.689 -> -34.683 W). The difference is small on this mesh because the near-wall cell temperature is close to the wall temperature, but it is mesh dependent.