Digby Symons - Blade

CONTENTS
1 Introduction ............................................................................................................. 3
2 Wind Turbine Blade Aerodynamics .................................................................. 4
2.1 Aerofoil Aerodynamics .................................................................................... 4
2.2 Wind Turbine Blade Kinematics..................................................................... 7
3 Blade Element Momentum Theory .................................................................. 12
3.1 Momentum changes ...................................................................................... 12
3.2 Blade forces .................................................................................................... 13
3.3 Induction factors ............................................................................................. 14
3.4 Iterative procedure ......................................................................................... 15
4 Optimum Performance of a Wind Turbine..................................................... 19
4.1 Turbine Power................................................................................................. 19
4.2 Optimal Induction Factors............................................................................. 19
4.3 Dependency of Power on Tip Speed Ratio................................................ 20
5 Blade Loading....................................................................................................... 21
5.1 Aerodynamic Loading.................................................................................... 21
5.2 Centrifugal Loading........................................................................................ 23
5.3 Self Weight loading ........................................................................................ 24
5.4 Combined Loading......................................................................................... 25
5.5 Storm Loading ................................................................................................ 26
More detailed coverage of the material in this handout can be found in various
books, e.g.
Aerodynamics of Wind Turbines, Hansen M.O.L. 2000
Wind Energy Explained, Manwell J.F., McGowan J.G & Rogers A.L. 2002
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