4.2.4. Run Sequence and Cart3D Mode Control

The "RunControl" section of pyCart.json contains settings that control how many iterations to run Cart3D, what mode to use for each subset of iterations, and command-line inputs to the various Cart3D binaries. The entire contents of this section, with all default options applied where necessary, is written to a file called case.json in the folder created for each case.

Several subsections of this section are described separately.

The options for this section have the following JSON syntax.

"RunControl": {
    // Phase description
    "PhaseSequence": [0, 1],
    "PhaseIters": [200, 400],
    // Job type
    "MPI": false,
    "qsub": true,
    "Resubmit": false,
    "Continue": true,
    "nProc": 8,
    "Adaptive": false,
    // Environment variable settings
    "Environ": { },
    // System-wide resource settings
    "ulimit": {
        "s": 4194304
    },

    // Surface mesh preparation options
    "intersect": {},
    "verify": {},

    // Mesh setup options
    "autoInputs": {
        "r": 8,
        "nDiv": 4,
    },
    // Volume mesh generation options
    "cubes": {
        "maxR": 10,
        "cubes_a": 10,
        "cubes_b": 2,
        "reorder": true,
        "sf": 0
    },

    // Adaptation settings
    "Adaptation": { },
    // Main flow solver inputs
    "flowCart": { },
    // Adjoint solver inputs
    "adjointCart": { },
    // Archive settings
    "Archive": { }
}

Some of these options are common to all solvers, and the full description of such settings can be found on the corresponding Cape page. Separate sections for flowCart, adjointCart, and Adaptation are provided for some of the subset dictionaries.

The CAPE intersect section is also relevant.

4.2.4.1. Options for autoInputs

The description of autoInputs controls are shown below. The user can also tell pyCart not to use autoInputs (and use a premade input.c3d instead) by adding "autoInputs": {} to pyCart.json.

r: {8} | float

Mesh radius. This defines the dimensions of the flow domain; specifically the limits are set r times the largest dimension of the surface away from the surface.

nDiv: {4} | int

Number of divisions in the initial mesh. An exponent of 2 is highly recommended for efficiency purposes.

4.2.4.2. Options for cubes

The program that actually creates the volume mesh in Cart3D is called cubes. The options that apply to it directly are shown below.

maxR: {10} | int

Maximum number of refinements in volume mesh before XLevs

cubes_a: {10} | float

Angle criterion for cut cell refinement

cubes_b: {2} | int

Number of additional buffer layers

reorder: {true} | false

Whether or not to reorder cells for optimal performance

sf: {0} | int

Number of additional refinements for sharp features