Hub Mass Properties

The user can specify the mass properties of the hub. The mass contribution should include the hub casing, pitch actuators, casts connecting pitch bearing to the hub, pitch motors and so on.

The Mass is positioned along the hub body-fixed \(x_b\) axis. The AxialPositionOfCentreOfGravity is the distance \(x_{CoG}\) measured from the hub centre along the negative \(x_b\) axis as shown in Figure 1. In addition the moment of inertia about and perpendicular to the \(x_b\) axis may also be entered with its origin about the hub centre of gravity.

Figure 1: Geometry of hub from the turbine side. Diagram illustrates position of \(x_{CoG}\) for the hub mass and inertia terms.

The MomentOfInertiaAboutShaft represents the rotational inertia of the hub shaft. How this is considered in the context of the drivetrain is described in the Rotational Inertia of the Drivetrain article.

An example set of inputs for the hub mass properties is provided below.

"MassProperties": {
    "Mass": 14000.0,
    "AxialPositionOfCentreOfGravity": 0.0,
    "MomentOfInertiaAboutShaft": 12000.0,
    "MomentOfInertiaPerpendicularToShaft": 0.0
    }