Environmental Engineering Reference
In-Depth Information
CHAPTER 16
Tower design and analysis
Biswajit Basu
Trinity College Dublin, Ireland.
This chapter addresses some of the design and analysis issues of interest to struc-
tural and wind engineers involved in ensuring the serviceability and survivability
of wind turbine towers. Wind turbine towers are fl exible multi-body entities con-
sisting of rotor blades which collect the energy contained within the wind, and the
tower which supports the weight of the rotor system and nacelle and transfers all
gravity and environment loading to the foundation. Two themes on the design and
analysis aspects of the tower have been presented. The fi rst is the mathematical
representation of the behaviour of wind turbine towers when subjected to wind
loading and the second is the suppression of the vibrations caused by this wind
action. The fi rst theme focuses on a series of mathematical models representing
the rotor blades, the tower with the added mass of the nacelle, and the coupled
rotor blade and tower system which are used to determine the free and forced
vibration characteristics of the structure. Response estimation for the rotating
blades includes the effects of centrifugal stiffening, dynamic gravity effects due
to rotation and rotationally sampled turbulence. A gust factor approach is also
presented for design of the wind turbine towers. The second theme considers the
mitigation of vibrations under dynamic wind action by adding energy dampers to
the system, and fi nding the optimal properties of these dampers in order to maxi-
mise the reduction of vibration. Modelling and analysis of offshore towers have
also been discussed.
1 I ntroduction
With the exponential growth in the wind energy market, turbines with larger rotor
diameter and hence taller towers are becoming more common. This has a crucial
impact on the design and analysis of wind turbine towers. The primary function
of the wind turbine tower is to elevate the turbine rotor for a horizontal axis wind
Search WWH ::
Custom Search