Description
The hub data file defines the geometric and inertial properties of a rotor hub. The hub is modeled as a simple lumped body connected to the rotor apex frame.
Parameters
| Name | Description | Value | Unit |
|---|---|---|---|
D_hub |
Diameter of hub. | Real scalar | [m] |
r_cm_x |
Distance from rotor apex frame to hub’s center of mass in x direction. | Real scalar | [m] |
r_cm_y |
Distance from rotor apex frame to hub’s center of mass in y direction. | Real scalar | [m] |
r_cm_z |
Distance from rotor apex frame to hub’s center of mass in z direction. | Real scalar | [m] |
m_hub |
Mass of the hub. | Real scalar | [kg] |
Ixx |
Mass moment of inertia of hub about its center of mass, along the rotor frame x-axis (pitched). | Real scalar | [kg.m²] |
Iyy |
Mass moment of inertia of hub about its center of mass, along the rotor frame y-axis. | Real scalar | [kg.m²] |
Izz |
Mass moment of inertia of hub about its center of mass, along the rotor frame z-axis (pitched). | Real scalar | [kg.m²] |
Ixy |
Product of inertia of hub about its center of mass. | Real scalar | [kg.m²] |
Ixz |
Product of inertia of hub about its center of mass (pitched). | Real scalar | [kg.m²] |
Iyz |
Product of inertia of hub about its center of mass. | Real scalar | [kg.m²] |
Notes
The inertia tensor is defined about the hub’s center of mass, along the coordinate vectors of the rotor apex frame (pitched by the nacelle tilt along the y-axis).
The hub data is stored in a .txt file that can easily be produced using the Data Generation Tool or by populating a .txt file manually. If the file is created manually, parameters must be defined in the format name = value;, where name is the parameter name and value is a number of type Real. Comments can be inserted in the file using double slash: //. See below for an example.
// =============================================
// Inertial properties
// =============================================
m = 123.456; // mass [kg]
I_xx = 1.23e4; // mass moment of inertia [kg.m²]
// =============================================
// Geometric properties
// =============================================
l = 12.345; // length [m]
The diagram shows a cross section of a nacelle connected to a rotor and tower top. The subscript “T” frame is defined at the tower top, with the x-axis pointing downwind and the z-axis vertical along the tower centerline. The subscript “S” frame is defined along the drive shaft, translated vertically from the tower top and pitched along the positive y-axis. The subscript “R” frame is defined at the rotor apex, translated along the pitched drive shaft from the shaft frame. The hub center of mass is defined in the rotor apex frame, although the vector is often 0, where the center of mass aligns with the rotor apex. The hub’s inertia tensor is defined about the center of mass, using the pitched coordinates of the rotor apex frame.
