Verification/Mesh Convergence

Solution verification checks for convergence by testing the solution on progressively finer grids. Three successively refined meshes of a given geometry are required to evaluate whether the coarsest mesh is within the asymptotic range. The grid convergence index (GCI) of each component of each selected field is evaluated: if they are all approximately equal to 1 then the coarse mesh is sufficiently refined for an accurate solution (and is within asymptotic range).

A verification JSON file contains two sections: "Mesh File Options", where the names of the three meshes to be used are provided, and "Verification Options", where the solution array IDs, transfer type, and number of threads are provided.

{
    "Program Type": "Verification",
    "Mesh File Options": {
        "Coarse Mesh File": "coarse.vtu",
        "Fine Mesh File": "fine.vtu",
        "Finer Mesh File": "finer.vtu"
    },
    "Verification Options": {
        "Array IDs": [0],
        "Transfer Type": "Consistent Interpolation",
        "Target GCI": 1.1,
        "Threads": 2
    }
}

Other options for "Transfer Type" are "Conservative Surface Transfer" (if enabled when compiling Promesh; requires IMPACT) and "Conservative Volume Transfer" (if enabled when compiling Promesh). The default GCI is 1.1, but a target GCI can be provided with keyword "Target GCI". "Threads" sets the number of threads used in the transfer (if OpenMP is enabled); if the keyword is unset and OpenMP is enabled, omp_get_max_threads will be used.