Design Wind Power Turbine - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 42

. y 3 .+.γ 2 y 2. +.γ 1 y.+.γ 0. =.S(y). (2.32)

Reference.20.shows.that.S(y).can.be.taken.as:

. S(y).=.(y.-.α)(y.-.β)..........(β.<.α). (2.33)

Where.the.α.and.β.are.the.distance.to.edge.points.of.the.length.proile.
Comparing.the.coeficients.in.Equation.(2.32).and.Equation.(2.33).and.solv-
ing.for.γ,.results.in:

γ = -(2 + ); α β

2

2

γ = 2 αβ α + ; . (2.34)

1

2

γ = - βα

0

Therefore,.if.coeficients.α.and.β.are.known,.we.can.determine.coeficients.
γ 2. ,. γ 1 ,. γ 0 . using. Equation. (2.34),. and. coeficients. a,. b,. C,. and. C 1 . also. can. be.
determined..The.contour.of.proile.represented.in.Equation.(2.35).is.derived.
from.Equation.(2.30).as:

λx 2 .-.k(y-α) 2 .(y.-.β).=.0. (2.35)

The.proile.function.can.be.described.by.using.Equation.(2.35),.which.was.
determined.for.asymmetrical.proiles.

1
4

2

. f ( x ) = (y - y )

1,2 2 1

x

x

where:

x
L

x
L

2

f (x) = a (1 + ) x < 0

1

k k

. . (2.36)

x
L

x
L

2

f (x) = a (1 - ) x > 0

1

k k

Here,.a.=.y 2. -.y 1 .is.a.thickness.of.points;.L k .is.a.width.for.every.cross.section.
In.Equation.(2.35),.the.coeficient.of.proile.k.can.be.shown.as:

27
16

λ
α β

e
-

2

k

. k = . (2.37)

2

( )