Wind turbine blade and method for determining arrangement of vortex generator on wind turbine blade

1. A wind turbine blade comprising:

a vortex generator including a plurality of fins,

wherein a height H(m) of each of the fins and a maximum chord length C max (m) of the wind turbine blade satisfy 0.3×10 −2 ≤H/C max ≤0.9×10 −2 ,

wherein the height H of each of the fins satisfies H≤0.1 δ 1 , provided that δ 1 is a boundary layer thickness at a rated tip speed ratio in a blade degradation state,

wherein the height H of each of the fins satisfies H≤δ 2 , provided that δ 2 is a boundary layer thickness at an optimum tip speed ratio in a blade normal state in which a surface of the wind turbine blade is smoother than in the blade degradation state,

wherein the height H(m) of each of the fins and a radius R(m) of a rotor including the wind turbine blade satisfies 0.2×10 −3 ≤H/R≤0.7×10 −3 ,

wherein all of the fins have a same size,

wherein the maximum chord length satisfies a relationship of 0.06≤C max /R≤0.08,

wherein the vortex generator includes:

a plurality of fin sets each of which is formed by a pair of fins arranged such that suction surfaces of the pair of fins face each other; and

a platform portion having a circular shape and provided for each of the plurality of fin sets, the pair of fins of said each of the plurality of fin sets being disposed on the platform portion,

wherein a distance between the pair of fins increases from leading edges of the pair of fins toward trailing edges of the pair of fins, and

wherein the vortex generator is arranged such that a ratio Z/S of an arrangement pitch Z of adjacent two of the fin sets to an interval S between the trailing edges of the pair of fins is not smaller than 1.5 and not greater than 3.0.

2. The wind turbine blade according to claim 1 ,

wherein the fins are configured such that an angle of a fin chord with reference to a chordwise direction of the wind turbine blade is not smaller than 12 degrees and not greater than 18 degrees.

3. The wind turbine blade according to claim 1 ,

wherein the fins are configured such that a ratio L/H of a chord length L of a fin root to the height H of each of the fins satisfies 2.0≤L/H≤4.0.

4. The wind turbine blade according to claim 1 ,

wherein a cross section of the platform portion has a curved convex shape, at least along a blade spanwise direction of the wind turbine blade.

5. The wind turbine blade according to claim 1 ,

wherein the suction surfaces of the pair of fins face each other, and a ratio S/H of an interval S between the trailing edges of the pair of fins to the height H of each of the pair of fins satisfies 2.5≤S/H≤5.0.

6. A method for determining arrangement of a vortex generator on the wind turbine blade according to claim 1 ,

wherein the vortex generator includes a pair of fins arranged line-symmetrically with respect to a segment along a chordwise direction of the wind turbine blade.

7. A method for determining arrangement of a vortex generator on the wind turbine blade according to claim 1 ,

wherein the vortex generator is arranged such that a ratio Z/H of an arrangement pitch Z of adjacent two of the fin sets to the height H of each of the pair of fins is not smaller than 6.0 and not greater than 8.0.

8. The wind turbine blade according to claim 1 ,

wherein the boundary layer thickness δ 1 and the boundary layer thickness δ 2 increase from a leading edge toward a trailing edge of the wind turbine blade in a chordwise direction of the wind turbine blade, and

wherein each of the fins is disposed at a chordwise position such that 0.1δ 1 ≤H≤δ 2 is satisfied.