4.2.14. RunMatrix or Run Matrix

A required section of pyCart.json describes the variables that define the run conditions and the values of those variables. In many cases, these will be familiar input variables like Mach number, angle of attack, and sideslip angle; but in other cases they will require additional description within the pyCart.json file. The generic run matrix description is found in the Cape RunMatrix section.

The following trajectory keys are in addition to the Cape list available to all solvers.

[translation]: Translate one or more components in a specified direction

{
    "Group": false,
    "Type": "translation",
    "Value": "float",
    "CompID": [],
    "CompIDSymmetric": [],
    "Vector": [],
    "Points": [],
    "PointsSymmetric": []
}

[rotation]: Rotate one or more components about a specified vector

{
    "Group": false,
    "Type": "rotation",
    "Value": "float",
    "CompID": [],
    "CompIDSymmetric": [],
    "VectorSymmetry": [1.0, -1.0, 1.0],
    "AngleSymmetry": -1.0,
    "Vector": [[0,0,0], [1,0,0]],
    "Points": [],
    "PointsSymmetric": []
}

These two variable types are somewhat complex but make it relatively simple to move components around and do all the necessary bookkeeping. The Vector option describes the direction in which a component is translated or the vector about which a component is rotated. The distance by which a component is translated (in the direction of Vector) or the angle by which a component is rotated is then the value of that variable in the run matrix. The options relating to Symmetry define components that are moved in an equal but opposite transformation. Finally, the Points option allows pyCart to automatically transform points along with the component. The most obvious reason for this is to keep a moment reference point in the same position in the body frame of the rotated component, but it is also useful when there are multiple rotations, the user wants to sample a point or cut plane at a fixed body position, or many other potential applications.

A long-form dictionary of the relevant translation and rotation options is given below.

CompID: {[]} | list (int | str)

List of components by name or index that are translated/rotated

CompIDSymmetric: {[]} | list (int | str)

List of components to translate/rotate in symmetric direction

AngleSymmetry: {-1.0} | float

Multiplier on angle for components rotated in symmetric direction. This is complementary to modifying the rotation vector using VectorSymmetry

Points: {[]} | list (str)

List of points by name that are translated/rotated

PointsSymmetric: {[]} | list (str)

List of points that are translated/rotated in symmetric direction

Vector: {[[0,0,0],[0,1,0]]} | list (list | str)

Two points defining the vector about which to rotate or the direction in which to translate. The points can be defined either as a list of three floats or a named point; named points will be moved by prior translations and rotations

VectorSymmetry: {[1.0,1.0,1.0]} | list (float), shape=(3,)

Multipliers applied to each component of the rotation vector