Rotor sensor
The rotor sensor can be added by toggling on the Sensor button in the Rotor part shown in the following picture:
For multi-rotor wind turbines, a sensor is available for each rotor
The Rotor sensor provides the following fields:
| Field | Unit | Description |
| Power (aero) | kW | aerodynamic power, i.e. the power exerted by the air on the blades |
| Torque (aero) | kNm | aerodynamic torque, i.e. the moment around the main shaft axis resulting from the aerodynamic forces on the blades |
| Thrust (aero) | kN | total aerodynamic force on the rotor in the main shaft direction |
| RPM | 1/m | revolutions per minute of the rotor, number of revolutions the turbine does in one minute. Also called Rotational speed or Rotational velocity |
| TSR | - | Tip speed ratio, ratio of the velocity of the tip of a blade over the wind speed magnitude at the hub |
| Pitch angle | degrees | angle by which the blades are rotated around the pitch axis. The pitch axis corresponds to the longitudinal axis if the blades are not prebend |
| Power coefficient (Cp) | - | ratio of the aerodynamic power over the total available power in the air (see CP - Power coefficient) |
| Thrust coefficient (Ct) | - | ratio of the thrust force over the dynamic force |
| Tip speed | m.s-1 | velocity of the tip of the blades. Calculated based on the RPM and the blade length |
| 1P (one revolution) | s | time it tales for the rotor to complete one revolution. Calculated by taking the inverse of the RPM and multiplying by 60 |
| nP (blade passing) | s | time it takes for a blade to pass in front of the tower. Calculated by dividing 1P by the number of blades |
| Azimuth angle | degrees | angular position of the rotor. An azimuth angle of 0 means that the blade 0 is pointing upwards |
| Rotation per timestep | degrees | degrees the rotor has rotated in one time step. The time step can be changed in the Analysis parameters |
| Wind speed at hub, magnitude | m.s-1 | magnitude of the wind speed at the hub location |
| Wind speed at hub | m.s-1 | components of the wind speed at the hub location. The components are given in the global coordinate system (see Coordinate systems) |
| Wind angle at hub | degrees | angle between the horizontal component of the wind and the horizontal projection of rotor plane normal at the hub |
| Yaw angle relative to forward | degrees | angle between the RNA and the tower top. This is typically the angle that the yaw actuator has yawed. If there is no yaw controller, this angle will stay 0 (even though the RNA might have rotated around the vertical axis, as can be the case if floater with a wind turbine on top rotates) |
| Yaw to reference direction | degrees | angle between the RNA and the reference direction. This is especially relevant in the context of floating wind turbines, where the rotor plane can have turned with respect to its initial position if the floater moves. You can then have a change in the orientation of the rotor plane even if there is no yaw controller |
| Yaw error | degrees | angle between the horizontal projection of the rotor plane normal and the incoming wind at hub height. This is the error used by the controller to yaw the RNA |
| Torque about yaw axis | Nm | torque about the yaw axis due to aerodynamic forces on the rotor (thus not including gyroscopic effects) |