Vortex generators for wind turbine rotor blades having noise-reducing features
Vortex generators for wind turbine rotor blades having noise-reducing features are mounted within a laminar flow region on either the pressure side or the suction side of the rotor blade and have a base portion with at least one airflow modifying element extending therefrom. The base portion has a leading edge and a trailing edge extending in a first direction. Further, the base portion includes one or more edge features formed within either or both of the leading or trailing edges. Moreover, the edge features are non-parallel with respect to the first direction so as to reduce laminar boundary layer instability noise.
1. A rotor blade assembly for a wind turbine, comprising:
a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root; and,
at least one blade add-on component mounted in a laminar flow region on at least one of the pressure side or the suction side of the rotor blade, the laminar flow region encompassing areas of the rotor blade where laminar airflow transitions to turbulent airflow, the blade add-on component comprising a base portion having a leading edge and a trailing edge, extending in a first direction,
wherein the base portion comprises one or more edge indentions formed into at least one of the leading edge or the trailing edge of the base and terminating before an edge of at least one airflow modifying element, the one or more edge indentions being non-parallel with respect to the first direction so as to reduce laminar boundary layer instability noise; wherein one or more edge indentions is chamfered towards at least one of the pressure side or the suction side of the rotor blade.
2. A rotor blade assembly for a wind turbine, comprising:
a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root; and,
at least one vortex generator mounted in a laminar flow region on at least one of the pressure side or the suction side of the rotor blade, the laminar flow region encompassing areas of the rotor blade where laminar airflow transitions to turbulent airflow, the vortex generator comprising a base portion and at least one airflow modifying element extending from the base portion, the base portion having a leading edge and a trailing edge extending in a first direction,
wherein the base portion comprises one or more edge indentions formed into at least one of the leading edge or the trailing edge of the base and terminating before an edge of the at least one airflow modifying element, at least one of the one or more edge indentions being non-parallel with respect to the first direction so as to reduce laminar boundary layer instability noise; wherein one or more edge indentions is chamfered towards at least one of the pressure side or the suction side of the rotor blade.
3. The rotor blade assembly of claim 2 , wherein the base portion comprises the one or more edge indentions formed into both the leading edge and the trailing edge thereof.
4. The rotor blade assembly of claim 2 , wherein the base portion further comprises the one or more edge indentions formed around an entire periphery thereof, a first plurality of the one or more edge indentions being non-parallel with respect to the first direction and a second plurality of the one or more edge indentions being parallel with respect to the first direction.
5. The rotor blade assembly of claim 2 , wherein the one or more edge indentions comprise at least one of serrations, recesses, slits, slots, holes, or channel.
6. The rotor blade assembly of claim 5 , wherein the one or more indentions comprise the serrations, the serrations comprising at least one of a U-shape, a V-shape, a C-shape, a sinusoidal shape, a rectangular shape, or a square shape.
7. The rotor blade assembly of claim 2 , wherein the base portion of the vortex generator comprises a plurality of edge indentions formed into at least one of the leading edge or trailing edge thereof, the plurality of edge indentions having a random pattern.
8. The rotor blade assembly of claim 2 , wherein the base portion of the vortex generator comprises a plurality of edge indentions formed into at least one of the leading edge or trailing edge thereof, the plurality of edge indentions having a uniform pattern.
9. The rotor blade assembly of claim 2 , wherein at least one of the airflow modifying elements comprises a fin extending generally perpendicular from the base portion.
10. A rotor blade assembly for a wind turbine, comprising:
a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root;
at least one vortex generator mounted in a laminar flow region on at least one of the pressure side or the suction side of the rotor blade, the laminar flow region encompassing areas of the rotor blade where laminar airflow transitions to turbulent airflow, the vortex generator comprising a base portion and at least one airflow modifying element extending from the base portion, the base portion having a leading edge and a trailing edge, wherein the base portion comprises one or more edge indentions formed into at least one of the leading edge or the trailing edge of the base and terminating before an edge of the at least one airflow modifying element; and,
at least one boundary-layer trip element mounted upstream of the vortex generator, the boundary-layer trip element configured to disrupt the airflow upstream of the vortex generator so as to force laminar airflow to turbulent airflow, thereby eliminating noise caused by laminar boundary layer instability; wherein the one or more edge indentions is chamfered towards at least one of the pressure side or the suction side of the rotor blade.
11. The rotor blade assembly of claim 10 , wherein the at least one boundary-layer trip element is mounted at a predetermined distance upstream of the vortex generator, the predetermined distance configured to disrupt the airflow upstream of the vortex generator so as to force laminar airflow to turbulent airflow, the predetermined distance ranging from about 1centimeter to about 40 centimeters.
12. The rotor blade assembly of claim 10 , wherein a height of the boundary-layer trip element ranges between approximately 0.1 millimeters and approximately 2.5 millimeters.
13. The rotor blade assembly of claim 10 , wherein the predetermined distance is determined as a function of a boundary layer thickness at a mounting location of the vortex generator.
14. The rotor blade assembly of claim 10 , wherein the boundary-layer trip element comprises at least one of tape, one or more wires, one or more blowing holes or slots, one or more recesses, or a surface roughness.
15. The rotor blade assembly of claim 10 , wherein the one or more edge indentions comprise at least one of serrations, recesses, slits, slots, holes, or channels.
16. The rotor blade assembly of claim 10 , wherein the base portion of the vortex generator comprises a plurality of edge indentions formed into at least one of the leading edge or trailing edge thereof, the plurality of edge indentions having a random pattern.
17. The rotor blade assembly of claim 10 , wherein the base portion of the vortex generator comprises a plurality of edge indentions formed into at least one of the leading edge or trailing edge thereof, the plurality of edge indentions having a uniform pattern.