System and method for use of a tunable mechanical mass damper to reduce vibrations in wind turbine blades in a locked or idling condition of the rotor hub

A method for reducing vibrations and loads in one or more rotor blades on a rotor hub of a wind turbine when the rotor hub is in a locked or idling condition, the method comprising:

• attaching a mass damper at a fixed location on one or more of the rotor blades, wherein attaching the mass damper comprises fixing clamping shells over the rotor blade at the fixed location, the clamping shells conforming to a shape of pressure side and suction side surfaces of the rotor blade and extending beyond leading and trailing edges of the rotor blade in a chord-wise direction, the mass damper attached to one of the clamping shells;
• and
• maintaining the mass damper on the rotor blades during the locked or idling condition of the rotor hub,
• wherein the mass damper includes a movable mass component responsive to changes in vibrations or oscillations induced in the rotor blades during the locked or idling condition of the rotor hub.