Wind Energy Explained, 2 nd Edition Errata

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Derrick Webster
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1 Wid Eergy Explaied, d Editio Errata This summarizes the ko errata i Wid Eergy Explaied, d Editio. The errata ere origially compiled o July 6, 0. Where possible, the chage or locatio of the chage is oted i red. These errata should oly apply to pritigs before this date. Additioal errata, idetified after November, 0, are listed at the ed. p The correct symbol for frictio velocity is u * rather tha U *. p. 60 Equatio.64 should read: Γ( + /k) σ u = U ( ) Γ + /k p. 0, i the folloig figure, the ope arrohead uder rω (+a ) should poit toards the origi, as sho belo. Ω chord lie df N df L ϕ df D r Ω(+a ) df T ϕ Plae of blade rotatio φ θ P θ p,0 θ Τ α U (- a ) = Wid velocity at blades U rel = Relative id velocity θ p = Sectio pitch agle U rel U (- a ) α = Agle of attack φ = θ p + α =Agle of relative id θ p,0 = Blade pitch agle θ T = Sectio tist agle

2 p. 6, lie 3-33, the equatio should be ϕ = α + θ p p. 73, lie 4 Equatio 4.4 should read: σ = M c / I β, max β p. 73, lie 5 ad I is the area momet of iertia p. 80 The gravity term G is give by G = g m B r g /I b p. 9 γ V The elemet (3,) i the matrix i Eq. 4. should be: 0 6 p. The setece i lie 4 should read: The DC field curret is ormally provided by a small AC geerator. p. 8, lie 8 The term should be RR s. p. 8, lie 0 From measuremets of voltage, curret ad poer, it is p. 8, lie 5 Oce the voltage, curret, ad poer are measured p. 38, lie 7 Some filterig may be doe (as ith the iductors sho i Figure 5.7) p. 44, lie 5 Figure 5.7 should be Figure 5.9 Page 47-48, lies 45 ad 46 ad lie 0 (p. 48). I all cases, stator should be used istead of rotor. The seteces should read: I this cofiguratio the geerator side coverter (PWM ) provides reactive poer to the geerator stator as ell as acceptig real poer from it. It cotrols the frequecy to the geerator stator, ad hece its speed. PWM also coverts the stator poer to DC.

3 p. 50, lie 5 The resistace is: R X (ot R x ) p. 5, lie 7 The expressio should read: R + R ( ) s R X / p. 5 I Equatio (5.8) ad (5.8) Rr should be p. 305, lies 9-0 I is the area momet of iertia of R R p From page 393 to the ed of Chapter 8, most of the equatio umbers quoted i the text are icorrect. For example, o page 393, lie 34, Equatio (8.0) ithout the derivative term should be Equatio (8.) ithout the derivative term Specifically, the correct equatio umbers are: p 393 lie Equatio 8. p 393 lie Equatio 8. p 394 lie Equatio 8. p 396 lie 5 Equatio 8.3 p 40 lie 9-0 Equatio 8.7 p. 44, lies 0 ad 6 The costats a ad b ere reversed. The seteces should read: I this relatioship the slope, a, is the ratio of the stadard deviatios The offset, b, is a fuctio of the mea id speeds at the cocurret referece site p. 44, lie 7 I this example, the peak loads, those over 0GW, occur 5% of the time ad accout for oly.5% of the aual eergy. p. 473 Equatio 0.4 should read: F ˆ = C ρ DU U + C ρ AU& (Note that the sea ater desity is ρ.) d m p. 56, lie 4 a 0 db soud poer itesity level ill yield p. 563, lies 8-9 3

4 here p is the istataeous soud pressure ad p 0 is a referece soud pressure (usually 0 x 0-6 Pa for soud i air ad x 0-6 Pa for soud i ater). p. 595 The correct symbol for frictio velocity is u * rather tha U *. p. 598, lie 7 The lie should read: I b Mass momet of iertia of a sigle blade p. 605, lie 7 This should read: I Area momet of iertia p. 606, lie 5 This should read: I Area momet of iertia p. 68 PR Problem.9: The equatio should read: CF = 0.087U D here U is the average id speed (m/s) at the hub p. 6 Problem.3: The correct symbol for frictio velocity is u * rather tha U *. p. 6, lie 36, the problem statemet should read: 3.4 a) Fid φ, θ P, θ T, ad p. 63, lie, The problem statemet should read: 3.5 a) Fid φ, θ P, θ T, ad p. 69 Problem 4.6, lie 4 (b) mass momet of iertia p. 637 Problem 6.: Add the setece: The momets of iertia are to be take about the log axis of the shaft. Problem 6.: Lies 7-8 should read: It is made of steel ith a shear modulus of elasticity of G = 80 GPa Lies 5-6 4

5 Hit: The rotatioal stiffess of a shaft, k θ, is give by k θ =JG/l p. 639 Problem 6.9: The modulus of elasticity of steel is 06.9 GPa. p. 645 Problem 8.8, lie 0 The total polar mass momet of iertia p. 646 Problem 8.0, lie 5: K D = 0.0 p. 654 Problem 0.6: Third setece should read: The id speed is m/s, the ave height is m ad the ave legth is 00 m. p. 655 Problem 0.: The first setece should read: A atural gas-fired turbie operatig o a ideal Brayto cycle p. 655 Problem 0.3: The volume of the Hideburg is 99,000 m 3. Additioal errata, idetified after November, 0, are listed belo. p. 38 The third lie should read: For a adiabatic process (o heat trasfer) dq=0, ad Equatio (.4) becomes: p. 4 The first setece of should be replaced ith The autocorrelatio fuctio provides a measure of the relatio betee the id speed at oe poit i time to that at aother poit i time. p. 06 The captio for Figure 3. should read: (a) Flo aroud statioary cylider; (b) flo aroud rotatig (CW) cylider p. 67 Equatios 4.5 ad 4.7 should read: F0 si () ( ω t φ) x t = k ω / ω + ξ ω / ω x k F = [ ( ) ] [ ( )] [ ( ω / ω ) ] + [ ξ ( ω ω )] 0 / 5

6 p. 73 Equatio 4.45 should read: Q = CQ ρπ 3 R U p. 6 Sectio The vector dl should be bold: d F = Idl db p. 30 Equatio 5.66 should read Q = P / π / 60 m i ( ) p. 305 Equatio 6.4 should read: D = f / f + ξ f [ ( ) ] [ ( / f )] e p. 435 Equatio 9.8 should read: V 4 G G e [ ( QX PR) V ] + ( QX PR) + ( PX + ) = 0 + V QR S p. 6 Problem 3. The secod lie should read: horizotally if the blade s drag to lift ratio, C d /C l, is 0.03? p. 634 Problem 5. The parameters are X X = 0.5 Ω, R = 0.04 Ω, R = Ω, X = 5 Ω. LS = LR S R M p. 670 Uder Step 5, the first executable lie should read: j% = CIt(Y_rage / biwidth) 6

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