Abstract: A wind turbine blade having a longitudinal direction with a root end and a tip end as well as a chord extending in a transverse direction between a leading edge and a trailing edge is described. The blade comprises a flow control surface with a suction side and a pressure side. A number of boundary layer control means is formed in the flow control surface. The boundary layer control means include a channel submerged in the flow control surface with a first end facing towards the leading edge and a second end facing towards the trailing edge of the blade.

Abstract: A wind turbine blade having a longitudinal direction with a root end and a tip end as well as a chord extending in a transverse direction between a leading edge and a trailing edge is described. The blade comprises a flow control surface with a suction side and a pressure side. A number of boundary layer control structures are formed in the flow control surface. The boundary layer control structures include a channel submerged in the flow control surface with a first end facing towards the leading edge and a second end facing towards the trailing edge of the blade. The channel further comprises a bottom surface extending from the first end to the second end. The channel at the first end comprises a first channel zone comprising a first sub-channel having a first cross-sectional area and a second sub-channel having a second cross-sectional area, the first sub-channel and the second sub-channel crossing each other at a point of crossing.

Abstract: A blade (10) for a rotor of a wind turbine having a profiled contour divided into: a root region (30), an airfoil region (34), and a transition region (32) between the root region (30) and the airfoil region (34). A shoulder (40) is located at the boundary between the transition region (32) and the airfoil region (34). The blade's profiled contour comprises a local relative thickness defined as the local ratio between a maximum profile thickness (t) and the chord length (c). The ratio between the shoulder width (W) and the blade length (L) being less than or equal to 0.075, and the relative thickness (t/c) in a blade length interval of 0-0.8L is at least 22%.

Abstract: A wind turbine includes a number of blades and an optical measurement system comprising a light source, such as a laser, an optical transmitter part, an optical receiver part, and a signal processor. The light source is optically coupled to the optical transmitter part, which includes an emission point for emitting light in a probing direction. The optical receiver part comprises a receiving point and a detector. The optical receiver part is adapted for receiving a reflected part of light from a probing region along the probing direction and directing the reflected part of light to the detector to generate a signal used to determine a first velocity component of the inflow. The emission point is located in a first blade at a first radial distance from a center axis, and the receiving point is located in the first blade at a second radial distance from the center axis.

Abstract: A wind turbine blade (10) for a rotor of a wind turbine (2) is provided with a longitudinally extending flow guiding device (70, 170) attached to the profiled contour. The flow guiding device comprises: 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. A longitudinally extending substantially plate-shaped element (97, 197) protrudes from the second surface (96, 196) of the base (90, 190).

Abstract: A wind turbine blade with a flow guiding device attached to a profiled contour on a pressure side of the blade is described. The flow guiding device has a front surface facing toward an oncoming airflow and comprises at least a first portion, which is angled towards the oncoming airflow and a leading edge of the wind turbine blade.

Abstract: A wind turbine blade with a plurality of flow guiding device parts attached to a profiled contour on a pressure side of the blade is described. The longitudinally extending flow guiding device parts are grouped together to form a first flow guiding device group in the transition region of the blade.

Abstract: A wind turbine is operated with a blade in which a transition region is provided between a root region with a substantially circular or elliptical profile closest to a hub and an airfoil region with a lift generating profile furthest away from the hub. The transition region has a base part with an inherent non-ideal aerodynamic design so that a substantial longitudinal part of the base part without flow altering devices at a design point deviates from a target axial induction factor. A pitch of the blade and a rotational speed are adjusted to meet the target axial induction factor of the second longitudinal segment, and flow altering devices are provided so as to meet the target axial induction factor of the first longitudinal segment.

Abstract: A blade for a rotor of a wind turbine has a root region with a substantially circular or elliptical profile closest to the hub and an airfoil region with a lift generating profile furthest away from the hub. A transition region has a base part with an inner dimension that varies linearly in the radial direction of the blade in such a way that an induction factor of the first base part without flow altering devices at a rotor design point deviates from a target induction factor. The first longitudinal segment is provided with a number of first flow altering devices arranged so as to adjust the aerodynamic properties of the first longitudinal segment to substantially meet the target induction factor at the design point.

Abstract: A blade for a rotor of a wind turbine is divided into a root region closest to the hub and an airfoil region with a lift generating profile furthest away from the hub. A transition region has 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, and includes at least a first longitudinal segment extending along at least 20% of a longitudinal extent of the airfoil region. A base part has an inherent non-ideal twist, such as no twist, or a reduced twist compared to a target blade twist, so that an axial induction factor of the first base part at a design point deviates from a target axial induction factor. A number of flow altering devices are arranged so as to adjust the aerodynamic properties of the first longitudinal segment.

Abstract: A blade, for a rotor of a wind turbine has a profiled contour in a radial direction is divided into a root region with a substantially circular or elliptical profile closest to the hub and an airfoil region with a lift generating profile furthest away from the hub. A transition region between the root region and the airfoil region has 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, and the airfoil region comprises at least a first longitudinal segment extending at least 20% of a longitudinal extent of the airfoil region. The first longitudinal segment has a first base part with a cross-sectional profile such that, when impacted by an incident airflow at an angle of attack of 0 degrees has a lift coefficient, which is 0 or less.

Abstract: A blade for a rotor of a wind turbine is divided into a root region closest to the hub and an airfoil region with a lift generating profile furthest away from the hub and a transition region. A base part of the transition region has an axial induction factor, which without flow altering device deviates at least 5% from a target axial induction factor. A number of first flow altering devices are arranged so as to adjust the aerodynamic properties of a longitudinal segment of the transition region to substantially meet the target axial induction factor.

Abstract: A wind turbine blade with a flow guiding device attached to a profiled contour on a pressure side of the blade is described. The flow guiding device extends along at least a longitudinal part of a transition region of the blade and is arranged so as to generate a separation of airflow along at least a central longitudinal portion of the flow guiding device from the pressure side of the blade at a point between the flow guiding device and a trailing edge of the blade, when the blade is impacted by an incident airflow. The inflow surface, in at least the central longitudinal portion, is formed so that, for each transverse cross-section, a end point tangent to the inflow surface at the end point crosses the profiled contour at a crossing point, where the profiled contour has a profile tangent to the profiled contour, and wherein an angle between the profile tangent and the end point tangent is at least 45 degrees.

Abstract: A wind turbine blade with a flow guiding device attached to a profiled contour on a pressure side of the blade is described. The flow guiding device extends along at least a longitudinal part of a transition region of the blade and is arranged so as to generate a separation of airflow along at least a central longitudinal portion of the flow guiding device from the pressure side of the blade at a point between the flow guiding device and a trailing edge of the blade, when the blade is impacted by an incident airflow. The flow guiding device is arranged at a relative chordal position, seen from the leading edge of the blade, lying in an interval between 40% and 92%. The relative height of the flow guiding device is at least 10% of a maximum thickness of the profiled contour.

Abstract: A blade for a rotor of a wind turbine having a substantially horizontal rotor shaft, the rotor comprising a hub, from which the blade extends substantially in a radial direction when mounted to the hub. The blade comprises a main blade part having a profiled contour comprising a pressure side and a suction side as well as a leading edge and a trailing edge with a chord extending between the leading edge and the trailing edge. The profiled contour generates a lift when being impacted by an incident airflow. The profiled contour is divided in the radial direction into a root region with a substantially circular or elliptical profile closest to the hub, the substantially circular or elliptical profile having a diameter, an airfoil region with a lift generating profile furthest away from the hub, and a transition region between the root region and the airfoil region.

Abstract: A wind turbine blade having a longitudinal direction with a root end and a tip end as well as a chord extending in a transverse direction between a leading edge and a trailing edge is described. The blade comprises a flow control surface with a suction side and a pressure side. A number of boundary layer control means is formed in the flow control surface. The boundary layer control means include a channel submerged in the flow control surface with a first end facing towards the leading edge and a second end facing towards the trailing edge of the blade. The channel further comprises a bottom surface extending from the first end to the second end. The channel at the first end comprises a first channel zone comprising a first sub-channel having a first cross-sectional area and a second sub-channel having a second cross-sectional area, the first sub-channel and the second sub-channel crossing each other at a point of crossing.

Abstract: A blade for a rotor of a wind turbine has a substantially horizontal rotor shaft, the rotor including a hub, from which the blade extends substantially in a radial direction when mounted to the hub. The blade includes a profiled contour including a leading edge and a trailing edge as well as a pressure side and a suction side, the profiled contour when being impacted by an incident airflow generating a lift. The profiled contour is divided into a root region with a substantially circular profile closest to the hub, an airfoil region with a lift generating profile furthest away from the hub, and a transition region between the root region and the airfoil region. The profile of the transition region gradually changes in the radial direction from the circular profile of the root region to the lift generating profile of the airfoil region. The suction side comprises at least a first zone, which extends substantially in the direction of the incident airflow, and which is positioned in a zone of a cross-flow.

Abstract: A wind turbine blade having a longitudinal direction with a root end and a tip end as well as a chord extending in a transverse direction between a leading edge and a trailing edge is described. The blade comprises a flow control surface with a suction side and a pressure side. A number of boundary layer control means is formed in the flow control surface. The boundary layer control means include a channel submerged in the flow control surface with a first end facing towards the leading edge and a second end facing towards the trailing edge of the blade.

Abstract: The present invention relates to a design concept by which the power, loads and/or stability of a wind turbine may be controlled by typically fast variation of the geometry of the blades using active geometry control (e.g. smart materials or by embedded mechanical actuators), or using passive geometry control (e.g. changes arising from loading and/or deformation of the blade) or by a combination of the two methods. The invention relates in particular to a wind turbine blade, a wind turbine and a method of controlling a wind turbine.

Abstract: The present invention relates to a design concept by which the power, loads and/or stability of a wind turbine may be controlled by typically fast variation of the geometry of the blades using active geometry control (e.g. smart materials or by embedded mechanical actuators), or using passive geometry control (e.g. changes arising from loading and/or deformation of the blade) or by a combination of the two methods. The invention relates in particular to a wind turbine blade, a wind turbine and a method of controlling a wind turbine.