Turbine data: Hub

Radius

The radius of the hub. It specifies the offset of the blade root, from the turbine's origin, along the pre-coned blade direction.

Mass and moments of inertia

The mass and the mass moments of inertia of the hub about the centre of mass. The axial moment of inertia is about the main shaft. The transverse moment of inertia is about any axis through the centre of mass and perpendicular to the main shaft.

Centre of mass

The offset of the centre of mass, relative to the turbine frame, along the main rotor shaft. This value is positive in the turbine $z$-axis direction.

Main shaft stiffness and damping

The linear rotational stiffness and damping of the main shaft. If the stiffness is infinity, a rigid connection is made between the hub and the gearbox's main shaft output. In this case, the damping value is unused. If the stiffness is finite, a degree of freedom is introduced and the hub can rotate, about the main shaft axis, relative to the gearbox's main shaft output.