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 comprising: - 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 generating a lift when being impacted by an incident airflow, - the profiled contour in the radial direction being divided into a root region with a substantially circular or elliptical profile closest to the hub, an airfoil region with a lift generating profile furthest away from the hub, and preferably a transition region between the root region and the airfoil region , the transition region 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 , wherein - the airfoil region comprises a plurality of segments comprising at least a first longitudinal segment extending along at least 20% of a longitudinal extent of the airfoil region , the first longitudinal segment comprising a first base part having a leading edge and a trailing edge with a chord extending between the leading edge and the trailing edge , characterised in that - the first base part has an axial induction factor, which without flow altering device deviates at least 5% from a target axial induction factor at a design point, and - the first longitudinal segment is provided with a number of first flow altering devices (146-149, 246, 248, 346-349, 446, 448) arranged so as to adjust the aerodynamic properties of the first longitudinal segment to substantially meet the target axial induction factor at the design point. - 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 generating a lift when being impacted by an incident airflow, - the profiled contour in the radial direction being divided into a root region with a substantially circular or elliptical profile closest to the hub, an airfoil region with a lift generating profile furthest away from the hub, and preferably a transition region between the root region and the airfoil region , the transition region 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 , wherein - the airfoil region comprises a plurality of segments comprising at least a first longitudinal segment extending along at least 20% of a longitudinal extent of the airfoil region , the first longitudinal segment comprising a first base part having a leading edge and a trailing edge with a chord extending between the leading edge and the trailing edge , characterised in that - the first base part has an axial induction factor, which without flow altering device deviates at least 5% from a target axial induction factor at a design point, and - the first longitudinal segment is provided with a number of first flow altering devices (146-149, 246, 248, 346-349, 446, 448) arranged so as to adjust the aerodynamic properties of the first longitudinal segment to substantially meet the target axial induction factor at the design point. <EOS>