Wind Energy Handbook. Michael Barton Graham

rel="nofollow" href="#ulink_a3e02814-b07e-54e6-b792-09f3fdf4c62c">Figure 2.5 Comparison of spectra at 12 m/sFigure 2.6 Comparison of spectra at 25 m/sFigure 2.7 Some asymptotic limitsFigure 2.8 Gust factors calculated from Eq. (2.46)Figure 2.9 Illustration of the Gumbel method

      4 Chapter 3Figure 3.1 The energy extracting streamtube of a wind turbine.Figure 3.2 An energy extracting actuator disc and streamtube.Figure 3.3 Variation of C _P and C _T with axial induction factor a.Figure 3.4 The trajectory of an air particle passing through the rotor disc....Figure 3.5 Tangential velocity grows across the disc thickness.Figure 3.6 Helical vortex wake shed by rotor with three blades each with uni...Figure 3.7 Simplified helical vortex wake ignoring wake expansion.Figure 3.8 The geometry of the vorticity in the cylinder surface.Figure 3.9 The radial and axial variation of axial velocity in the vicinity ...Figure 3.10 The axial variation of tangential velocity in the vicinity of an...Figure 3.11 The axial variation of tangential velocity in the vicinity of an...Figure 3.12 Flow field through an actuator disc for a = 1/3.Figure 3.13 A blade element sweeps out an annular ring.Figure 3.14 Blade element velocities and forces: (a) velocities, and (b) for...Figure 3.15 Power coefficient – tip speed ratio performance curve.Figure 3.16 Comparison of theoretical and measured values of C _T .Figure 3.17 Variation of blade geometry parameter with local speed ratio.Figure 3.18 Variation of inflow angle with local speed ratio.Figure 3.19 Optimum blade design for three blades and λ = 6: (a) blade ...Figure 3.20 Uniform taper blade design for optimal operation.Figure 3.21 Spanwise distribution of the lift coefficient required for the l...Figure 3.22 Spanwise distribution of the twist in degrees required for the l...Figure 3.23 Radial variation of the flow induction factors with and without ...Figure 3.24 Spanwise variation of the blade geometry parameter with and with...Figure 3.25 Variation of inflow angle with local speed ratio with and withou...Figure 3.26 The variation of maximum C _P with design λ for various lift/...Figure 3.27 Helical trailing tip vortices of a horizontal axis turbine wake....Figure 3.28 Azimuthal variation of a for various radial positions for a thre...Figure 3.29 Spanwise variation of the tip‐loss factor for a blade with unifo...Figure 3.30 Spanwise variation of power extraction in the presence of tip‐lo...Figure 3.31 A (discretised) helicoidal vortex sheet wake for a two bladed ro...Figure 3.32 Prandtl's wake‐disc model to account for tip‐losses.Figure 3.33 Comparison of Prandtl tip‐loss factor with that predicted by a v...Figure 3.34 Spanwise variation of blade circulation for a three blade turbin...Figure 3.35 Spanwise variation of combined tip/root loss factor for a three ...Figure 3.36 Axial flow factor variation with radius for a three blade turbin...Figure 3.37 Variation of blade geometry parameter with local speed ratio, wi...Figure 3.38 Variation of inflow angle with local speed ratio, with and witho...Figure 3.39 Spanwise variation of power extraction in the presence of tip‐lo...Figure 3.40 The variation of maximum C _P with designλ for various lift/d...Figure 3.41 The variation of circulation along the length of a blade.Figure 3.42 Pressure measurements on the surface of a wind turbine blade whi...Figure 3.43 A comparison of measured and Snel's predicted power curves for a...Figure 3.44 The aerodynamic characteristics of the NACA632XX aerofoil series...Figure 3.45 Angle of attack distribution for a range of tip speed ratios.Figure 3.46 Distribution of the flow induction factors for a range of tip sp...Figure 3.47 Distribution of blade loads for a range of tip speed ratios (lin...Figure 3.48 Variation of thrust coefficient with tip speed ratio.Figure 3.49 Variation of the actual force with wind speed.Figure 3.50 C _P ‐ λ performance curve for a modern three blade tur...Figure 3.51 C _P ‐ λ performance curve for a modern three blade tur...Figure 3.52 Effect of changing solidity.Figure 3.53 The effect of solidity on torque.Figure 3.54 The effect of solidity on thrust.Figure 3.55 Non‐dimensional performance curves for constant‐speed operation....Figure 3.56 Effect on extracted power of rotational speed.Figure

Скачать книгу