Patent ID: 8579594

Claim:
Wind turbine blade ( 10 ) having a longitudinal direction with a root end ( 16 ) and a tip end ( 14 ) as well as a chord extending in a transverse direction between a leading edge ( 18 ) and a trailing edge ( 20 ), the blade ( 10 ) comprising a flow control surface with a suction side and a pressure side, wherein a number of boundary layer control means ( 40 ) is formed in the flow control surface, wherein the boundary layer control means ( 40 ) include a channel submerged in the flow control surface ( 112 ; 212 ; 312 ; 412 ; 512 ; 612 ) with a first end ( 102 ; 202 ; 302 ; 402 ; 502 ; 602 ) facing towards the leading edge ( 18 ) and a second end ( 104 ; 204 ; 304 ; 404 ; 504 ; 604 ) facing towards the trailing edge ( 20 ) of the blade ( 10 ), the channel comprising: a bottom surface ( 106 ; 206 ; 306 ; 606 ) extending from the first end ( 102 ; 202 ; 302 ; 402 ; 502 ; 602 ) to the second end ( 104 ; 204 ; 304 ; 404 ; 504 ; 604 ), a first sidewall ( 108 ; 208 ; 308 ; 408 ; 508 ; 608 ) extending between the flow control surface ( 112 ; 212 ; 312 ; 412 ; 512 ; 612 ) and the bottom surface ( 106 ; 206 ; 306 ; 606 ) and extending between the first end ( 102 ; 202 ; 302 ; 402 ; 502 ; 602 ) and the second end ( 104 ; 204 ; 304 ; 404 ; 504 ; 604 ), the first sidewall ( 108 ; 208 ; 308 ; 408 ; 508 ; 608 ) forming a first sidewall edge ( 114 ; 214 ; 314 ) between the first side wall ( 108 ; 208 ; 308 ; 408 ; 508 ; 608 ) and the flow control surface ( 112 ; 212 ; 312 ; 412 ; 512 ; 612 ), and a second sidewall ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) extending between the flow control surface ( 112 ; 212 ; 312 ; 412 ; 512 ; 612 ) and the bottom surface ( 106 ; 206 ; 306 ; 606 ) and extending between the first end ( 102 ; 202 ; 302 ; 402 ; 502 ; 602 ) and the second end ( 104 ; 204 ; 304 ; 404 ; 504 ; 604 ), the second sidewall ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) forming a second sidewall edge ( 116 ; 216 ; 316 ) between the second side wall ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) and the flow control surface ( 112 ; 212 ; 312 ; 412 ; 512 ; 612 ), characterized in that the channel at the first end ( 102 ; 202 ; 302 ; 402 ; 502 ; 602 ) comprises a first flow accelerating channel zone ( 122 ; 222 ; 322 ; 622 ) adapted for accelerating a flow, wherein the first sidewall and the second sidewall of the first flow accelerating channel zone are non-divergent, and the channel at the second end ( 104 ; 204 ; 304 ; 404 ; 504 ; 604 ) comprises a second channel zone ( 124 ; 224 ; 324 ; 624 ), where the first sidewall ( 108 ; 208 ; 308 ; 408 ; 508 ; 608 ) and the second sidewall ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) in the second channel zone are diverging towards the trailing edge ( 20 ) of the blade ( 10 ) and wherein a vortex is generated and propagated within the second channel zone.