Environmental Engineering Reference
In-Depth Information
Figure 10: Wind turbine tower model installed in test section of wind tunnel.
valuable approach for wind engineers. Ever since the fi rst major building study in a
boundary layer wind tunnel was conducted by Cermak and Davenport in the 1960s,
engineers have been able to inexpensively investigate turbulence-induced pheno-
mena. The results provide vital information necessary to ensure the serviceability
and survivability of fl exible structures like a wind turbine.
Considerable experimental literature now exists regarding wind tunnel testing of
structures in general. Aerodynamic studies are primarily focused on evaluation of
drag and lift coeffi cients, such as those by Carril et al. [56] and Gioffrè et al. [ 57 ].
Aeroelastic scale model studies, similar to those by Ruscheweyh [58] and Kim and
You [59], examine the link between structural geometrical form and aeroelastic phe-
nomena, such as vortex shedding. Passive and active dampers are also proving to be
valuable devices in the mitigation of wind-induced structural vibration, and the wind
tunnel provides an excellent means to develop and test control strategies [60, 61].
While there is very limited literature available on wind tunnel testing of wind tur-
bines, this kind of testing can be very useful for system identifi cation [ 62 ], design,
and analysis of wind turbines and associated vibration control systems.
Figure 10 shows a model assembly of wind turbine constructed at the Depart-
ment of Civil Engineering, Trinity College Dublin, Ireland being tested in the wind
tunnel facility at National University of Ireland, Galway [63]. The model assembly
was composed of three main components: the tower, the nacelle and motor, and the
rotor system. The model was designed so that the fundamental frequencies of the
rotor blades and the tower were close to each other, ensuring signifi cant dynamic
coupling between the two subcomponents. The model was immersed in a turbulent
wind fl ow and the responses were recorded. The recorded bending strain at the
base of the tower and the corresponding Fourier amplitude spectrum are shown in
Figs 11 and 12 for the case of a stationary wind turbine.
Search WWH ::




Custom Search