Wind turbine blade with longitudinally extending flow guiding device having a plate-shaped element

1. A wind turbine blade ( 10 ) for a rotor of a wind turbine ( 2 ) having a substantially horizontal rotor shaft, said rotor having a hub ( 8 ), from which the blade ( 10 ) extends substantially in a radial direction when mounted to the hub ( 8 ), the blade having a longitudinal direction (r) with a tip end ( 14 ) and a root end ( 16 ) and a transverse direction, the blade comprising:

a profiled contour ( 40 , 42 , 50 ) including a pressure side and a suction side, as well as a leading edge ( 18 ) and a trailing edge ( 20 ) with a chord having a chord length extending there between, the profiled contour, when being impacted by an incident airflow, generating a lift, characterised in that

the wind turbine blade is provided with a longitudinally extending flow guiding device ( 70 , 170 ) on the pressure side of the blade attached to the profiled contour, the flow guiding device having:

a base ( 90 , 190 ) having

a first longitudinal end ( 91 , 191 ) nearest the root end ( 16 ) and a second longitudinal end ( 92 , 192 ) nearest the tip end ( 14 ),

a first side ( 93 , 193 ) nearest the leading edge ( 18 ) and a second side ( 94 , 194 ) nearest the trailing edge ( 20 ), as well as

a first surface ( 95 , 195 ) and a second surface ( 96 , 196 ), the first surface of the base being attached to the profiled contour, and the second surface facing away from the profiled contour, wherein

a plate-shaped element ( 97 , 197 ) protrudes from the second surface ( 96 , 196 ) of the base ( 90 , 190 ) in direction from the first end ( 91 , 191 ) towards the second end ( 92 , 192 ) such that it extends substantially in the longitudinal direction of the blade and the base, wherein the plate-shaped element is perpendicular to the airflow, wherein an angle between the longitudinal direction and a longitudinal axis of the blade is less than 30 degrees, wherein the plate-shaped element forms a first angle with the base, wherein the first angle with the base is not a perpendicular angle, and wherein

the flow guiding device ( 70 , 170 ) is arranged so as to generate a separation of airflow from the pressure side of the blade at a point between the flow guiding device ( 70 , 170 ) and the trailing edge ( 20 ) of the blade, when the blade is impacted by the incident airflow.

2. A wind turbine according to claim 1 , wherein the profiled contour is divided into:

a root region ( 30 ) having a substantially circular or elliptical profile closest to the hub,

an airfoil region ( 34 ) having a lift-generating profile furthest away from the hub, and

a transition region ( 32 ) between the root region ( 30 ) and the airfoil region ( 34 ), the transition region ( 32 ) having a profile gradually changing in the radial direction from the circular or elliptical profile of the root region to the lift-generating profile of the airfoil region.

3. A wind turbine blade according to claim 2 , wherein the flow guiding device ( 70 ) is arranged in the transition region ( 32 ) of the profiled contour on the pressure side of the blade ( 10 ).

4. A wind turbine blade according to claim 3 , wherein the flow guiding device extends substantially along an entire longitudinal extent of the transition region.

5. A wind turbine blade according to claim 2 , wherein the flow guiding device extends into the airfoil region.

6. A wind turbine blade according to claim 1 , wherein the plate-shaped element extends substantially along the entire longitudinal extent of the base.

7. A wind turbine blade according to claim 1 , wherein the plate-shaped element protrudes from the first side or the second side of the base.

8. A wind turbine blade according to claim 1 , wherein the plate-shaped element protrudes from a point between the first side and the second side of the base, e.g. a middle part.

9. A wind turbine blade according to claim 1 , wherein the plate-shaped element is substantially planar.

10. A wind turbine blade according to claim 1 , wherein the plate-shaped element is curved, e.g. convex or concave.

11. A wind turbine blade according to claim 1 , wherein the plate-shaped element at a point of attachment forms a first angle with the base, the first angle being maximum 80 degrees.

12. A wind turbine blade according to claim 11 , wherein the plate-shaped element is angled towards the trailing edge of the blade.

13. A wind turbine blade according to claim 11 , wherein the plate-shaped element is angled towards the leading edge of the blade.

14. A wind turbine blade according to claim 1 , wherein the base is formed of a flexible material.

15. A wind turbine blade according to claim 1 , wherein the first surface of the base is curved.

16. A wind turbine blade according to claim 15 , wherein the curve of the first surface varies in the longitudinal direction of the base.

17. A wind turbine blade according to claim 1 , wherein the plate-shaped element at a point of attachment forms a first angle with the base, the first angle being maximum 70 degrees.

18. A wind turbine blade according to claim 1 , wherein the plate-shaped element at a point of attachment forms a first angle with the base, the first angle being maximum 60 degrees.

19. A wind turbine according to claim 1 , wherein the flow guiding device is non-adjustable.

20. A wind turbine according to claim 1 , wherein the flow guiding device increases a lift of a longitudinal section of the blade.