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@PHDTHESIS{Shkara:795436,
author = {Shkara, Yasir},
othercontributors = {Schelenz, Ralf and Behr, Marek},
title = {{Q}uantification of aeroelastic response of blade-tower
interaction in multimegawatt wind turbines; 1. {A}uflage},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
publisher = {Verlag Mainz},
reportid = {RWTH-2020-08331},
isbn = {978-3-95886-361-3},
pages = {XVIII, 99 Seiten : Illustrationen, Diagramme},
year = {2020},
note = {Zweitveröffentlicht auf dem Publikationsserver der RWTH
Aachen University; Dissertation, RWTH Aachen University,
2020},
abstract = {The trend in the current development of modern horizontal
axis wind turbines (HAWTs) is towards light-weight, bigger
rotor diameter and longer towers. The bigger, lighter and
more flexible structure is more dynamically active and
sensitive to smaller excitations. Furthermore, with
increasing tower length the tower base becomes bigger and
transportation problems appear. Nowadays, tower dimensions
have almost reached roads limits. On the other hand, the
influence of external factors such as wind shear and
rotor-tower interaction become more important. To ensure
that the dynamic behavior of the wind turbine structure will
not influence the stability of the system and to further
optimize the structure dimensions, a fully detailed analysis
of the entire wind turbine structure is essential. Hence,
the aim of this work is to investigate the bidirectional
blade-tower interaction of a multi-megawatt upwind HAWT. A
high-fidelity aeroelastic model based on fluid-structure
interaction is presented. The blade aerodynamics was
predicted from solving the unsteady incompressible
Navier-Stokes equations by means of computational fluid
dynamics (CFD), while structure deformation was calculated
using finite element (FE). The dynamic response of the wind
turbine structure is accomplished in a strongly coupled
manner. Both elastic blade and tower are considered, where
the blades are modeled as an equivalent cantilever beam
while the tower is discretized into finite elements. The
numerical model provides insight into wind turbine
aerodynamic performance and structure behavior. The study
showed that passage of the blade in front of the tower
causes a noticeable dip in the rotor aerodynamic torque.
Furthermore, the rotor has a strong influence on the tower
shedding frequency causing different wake structures between
the upper and the lower parts. The dynamic response of the
tower is synchronized with azimuthal angle of the rotor and
the blades suffer oscillatory deformation particularly in
the flapwise direction. This creates cyclic fatigue loads
and structure deformation three times per rotation which are
considered to be important for the tower design and
fatigue-life analyse.},
cin = {412010},
ddc = {620},
cid = {$I:(DE-82)412010_20140620$},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
doi = {10.18154/RWTH-2020-08331},
url = {https://publications.rwth-aachen.de/record/795436},
}
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