Sensor device for an aerodynamic element
A sensor device for measuring flow-separation on an aerodynamic element, including a number of compliant elements with aerodynamic and/or structural properties designed to allow flow-induced vibrational motion in an air current and a sensor-element designed to measure vibrations of the number of compliant elements is provided. Further provided is an aerodynamic element, e.g. a wind turbine blade or an airfoil, with such sensor device, a method for controlling the angle of attack of an aerodynamic element, a controlling device and a wind turbine.
1. A wind turbine comprising:
an aerodynamic element;
a sensor device for detecting flow-separation on the aerodynamic element, the sensor device comprising:
a plurality of compliant elements with aerodynamic and/or structural properties designed to allow flow-induced vibrational motion in an air current downstream of a trailing edge of the aerodynamic element, wherein the plurality of compliant elements are designed as at least one of: filaments of a comb-structure, teeth of a serration, filaments of a combed serration, and a combed trailing edge treatment device;
a sensor-element designed to measure vibrations of the plurality of compliant elements at different times;
a comparator unit configured to determine if the vibrations of the plurality of compliant elements exceed a predefined threshold where flow-separation occurs without a loss of lift; and
a signal-unit configured to create a control signal based on the vibrations of the plurality of compliant elements if the comparator determines that the measured vibrations exceed the predefined threshold,
a control unit, the control unit configured to receive the control signal from the signal-unit of the sensor device and adjust a pitch angle and/or a rotation speed of the aerodynamic element according to the control signal.
2. The wind turbine of claim 1 , wherein the sensor-element comprises at least two different types of sensors operably connected to the plurality of compliant elements.
3. The wind turbine of claim 1 , wherein a compliant element of the plurality of compliant elements has an elongated shape with a ratio of length to width greater than 3 to 1, and is designed to be attached perpendicular to the trailing edge of the aerodynamic element.
4. The wind turbine of claim 3 , wherein each compliant element of the plurality of compliant elements comprises:
a minimum length of 1 cm,
and/or
a maximum length of 20 cm,
and/or
a minimum width of 1 mm,
and/or
a maximum width of 40 mm.
5. The wind turbine of claim 1 , wherein the plurality of compliant elements comprises more than two compliant elements protruding from a common root-element, wherein the more than two compliant elements are arranged parallel to each other having a minimum spacing to an adjacent compliant element of 1 mm, and/or a maximum spacing to an adjacent compliant element of 10 mm.
6. The wind turbine of claim 1 , wherein the sensor-element comprises at least two different types of sensors.
7. The wind turbine of claim 6 , wherein the at least two different types of sensors include:
a sensor for optical measurements,
or
a strain gauge-sensor connected with a compliant element of the plurality of compliant elements or a compliant element formed as strain gauge element,
or
an accelerometer that is mounted on the compliant element, measuring an acceleration of the compliant element,
or
an acoustic sensor measuring sound waves in the aerodynamic element.