Noise Reducing Fence for a Wind Turbine Blade
A noise reducing wind turbine blade is disclosed. The wind turbine blade includes a blade body having a leading edge, a trailing edge, a suction side, and a pressure side. The wind turbine blade further includes a fence disposed on a portion of the blade body upstream from the trailing edge for modifying airflow over the blade body in the vicinity of the trailing edge effective to reduce acoustic emission.
1 ) A wind turbine blade comprising:
a blade body having a leading edge, a trailing edge, a suction side, and a pressure side; and
a fence disposed on a portion of the blade body upstream from the trailing edge for modifying airflow over the blade body in the vicinity of the trailing edge effective to reduce acoustic emission.
2 ) The wind turbine blade of claim 1 , wherein the fence is disposed adjacent the trailing edge.
3 ) The wind turbine blade of claim 1 , further comprising a serrated tooth trailing edge appendage, wherein the fence is disposed along at least a portion of the trailing edge upstream of the serrated tooth trailing edge appendage.
4 ) The wind turbine blade of claim 4 , where the fence is disposed upstream of a valley between downstream points of the serrated teeth.
5 ) The wind turbine blade of claim 4 , where a length of the fence is less than a distance between downstream points of the serrated teeth.
6 ) The wind turbine blade of claim 1 , wherein the fence comprises a porosity of between about 50% and 90%.
7 ) The wind turbine blade of claim 1 , wherein the fence comprises a porosity of between about 70% and 90%.
8 ) The wind turbine blade of claim 1 , wherein the fence comprises a plurality of passageways substantially aligned with the airflow.
9 ) The wind turbine blade of claim 8 , wherein the passageways comprise one or more of a circular, polygonal, or rectilinear cross section.
10 ) The wind turbine blade of claim 8 , wherein the passageways are configured to substantially maintain an air flow velocity through the fence.
11 ) The wind turbine blade of claim 10 , wherein at least some of the passageways comprise an inlet smaller than an outlet.
12 ) The wind turbine blade of claim 10 , wherein at least some of the passageways comprise an outlet smaller than an inlet.
13 ) The wind turbine of claim 1 , wherein the fence comprises a row of bristles.
14 ) The wind turbine of claim 1 , wherein the fence extends vertically away from the blade body at an angle of between 50 and 140 degrees.
15 ) The wind turbine of claim 1 , wherein fence extends vertically away from the blade body at an angle of about 90 degrees.
16 ) The wind turbine of claim 1 , wherein the fence is configured to flexibly adapt to an angle of incidence of the airflow.
17 ) The wind turbine blade of claim 1 , wherein the fence comprises a height of between about 0.1% to 5% of a local chord length.
18 ) The wind turbine blade of claim 1 , wherein the fence comprises a height of between about 0.1% and 1.0% of a local chord length.
19 ) The wind turbine blade of claim 1 , wherein the fence is disposed on the suction side, the pressure side, or both the suction and pressure side.
20 ) The wind turbine blade of claim 1 , wherein the fence comprises a lightning receptor.
21 ) A noise reducer for a wind turbine blade comprising:
a fence for attachment to a portion of a wind turbine blade upstream from a trailing edge of the blade;
wherein the fence comprises airflow modifying structures configured to extend at least partially into a boundary layer of airflow over the blade upstream of the trailing edge effective to reduce acoustic emissions.
22 ) A wind turbine comprising:
at least one blade having a leading edge, a trailing edge, a suction side, and a pressure side; and
a fence disposed on a portion of the blade body upstream from the trailing edge for modifying airflow over the blade body in the vicinity of the trailing edge effective to reduce acoustic emission.