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Mian, Haris Hameed; Siddiqui, Muhammad Salman; Franchina, Nicoletta; Kouaissah, Otman; Wang, Gang & Nygaard, Tor Anders
(2024).
Aerodynamic and Structural Assessment of FOWT Rotor Under Varying Tilt Angle.
Show summary
The effect of wind and waves results in a sixdegree-
of-freedom motion of the platform, directly
influencing turbine performance. This research
examines the effects of rotor tilt angle on both
aerodynamic performance and structural response
employing computational fluid dynamics (CFD)
analysis and mapping aerodynamic loads onto the
finite element (FE) mesh for structural analysis of
NREL 5MW reference wind turbine rotor. Increased
rotor tilt angle reduces turbine performance. Fluidstructure
analysis shows higher flap-wise
displacement with larger tilt angles, impacting
thrust and power output. The displacement and
stress patterns aligns with observed data.
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Sakaris, Christos; Schlanbusch, Rune; Nygaard, Tor Anders; Sakellariou, John & Tutkun, Murat
(2023).
Statistical times series based damage detection in the fiber rope mooring lines of the semi-submersible OO-STAR wind floater.
Show summary
The Floating Offshore Wind Turbines (FOWTs)
based on semi-submersible floaters constitute a popular choice
in most markets due to their installation being flexible and in
need of low infrastructural requirements. A simple and robust
three-legged semi-submersible floater for FOWTs, the OOSTAR
wind floater, has been introduced and it can be anchored
to the seabed with steel chain mooring lines or hybrid mooring
lines - a combination of chains and synthetic fiber ropes. The
fiber rope mooring lines present a number of advantages thus
leading to a lighter and less costly mooring system. These
lines are important for the FOWT’s integrity as their loss can
lead to the change of the floater’s position, a damaged power
cable, a possible collision with other infrastructure and high
maintenance costs. This why an early detection of damages in
the mooring system is crucial. In this study, damage detection in
the main part of fiber rope mooring lines of semi-submersible
based FOWTs is investigated for the first time. In particular, the
OO-STAR floater based FOWT is considered. Two Statistical
Time Series based detection methods, the Multiple Model-
AutoRegressive (MM-AR) method and the Functional Model
Based Method (FMBM) are used and compared. The MM-AR
is based on multiple AR models whereas the FMBM on a single
Functional Model, for the description of the healthy FOWT’s
dynamics under varying environmental conditions. The results
based on seven healthy and eight damage cases under varying
wind speed and wave height show that the two methods are
able to achieve damage detection in fiber rope mooring lines
without any false alarm or missed damage despite of damages
having small effects on the FOWT’s dynamics and the fiber
ropes presenting a non-linear behaviour.
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Nygaard, Tor Anders; Fromreide, Mads & Eide, Kurt
(2022).
Creep and dynamic stiffness properties of nylon ropes. Comparisons of test results and computations.
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Nygaard, Tor Anders; Zhang, Bin; Andersen, Håkon; Nordgård-Hansen, Ellen Marie & Kaynia, Amir M.
(2021).
FibreRope Mooring for Floating Wind Turbines.
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Oggiano, Luca; Arens, Emile; Myhr, Anders; Nygaard, Tor Anders & Evans, Steve
(2015).
CFD Simulations on a Tension Leg Buoy Platform for Offshore Wind Turbines and Comparison with Experiments.
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Azcona, Jose; Bouchotrouch, Faisal; Gonzalez, M; Garciand, M; Munduate, Xavier & Kelberlau, Felix
[Show all 7 contributors for this article]
(2014).
Aerodynamic Thrust Modelling in Wave Tank Tests of Offshore Floating Wind Turbines Using a Ducted Fan.
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Robertson, Amy; Jonkman, Jason; Vorpahl, Fabian; Popko, Wojciech; Qvist, Jacob & Frøyd, Lars
[Show all 38 contributors for this article]
(2014).
Offshore Code Comparison Collaboration Continuation Within IEA Wind Task 30: Phase II Results Regarding a Floating Semisubmersible Wind System.
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Azcona, Jose; Munduate, Xavier; Hoyos, Merino & Nygaard, Tor Anders
(2011).
Dynamic simulation of mooring lines for floating wind turbines.
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Azcona, Jose; Munduate, Xavier; Hoyos, Merino & Nygaard, Tor Anders
(2011).
Development of OPASS code for dynamic simulation of mooring lines in contact with seabed.
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Nygaard, Tor Anders; Myhr, Anders & Maus, Karl Jacob
(2010).
Vil konkurrere ut Hywind.
Show summary
Under ledelse av IFE-forsker og UMB-professor i maskinteknikk, Tor Anders Nygaard, jobber Anders Myhr og Karl Jacob Maus, en annen stipendiat og to masterstudenter med å utvikle en ny teknologi for flytende havvindturbiner. I løpet av fire år er det skrevet 14 masteroppgaver om offshore vindkraft ved UMB. Målet er å kutte kostnader der det er mulig og samtidig få en fullverdig turbinløsning
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Myhr, Anders; Moss, David Wauthier & Nygaard, Tor Anders
(2009).
Large Scale Assembly and Erection of Floating Offshore Wind Turbines.
Show summary
The investigation has been carried out with a conceptual design of a semisubmersible platform operating on site in offshore locations. Analysis has been carried out with four different single buoy turbine concepts to verify loads occurring during challenging operating conditions set to 90% of the time within the North Sea region. Pivot rotation by the means of ballast transfer is a common technology used in the offshore industry. Utilizing the concept on floating wind turbines is yet to be explored and seems to have a large potential. Adequate measures must be taken in order to ensure that the pivot concept can handle the final geometries of the turbine towers. At this early stage it is not known what kind of floating turbine concept will be proven to be economically viable. Making the pivot concept adaptable to several different wind turbine concepts is thus important. One other main goal is to incorporate all of the assembly features from connecting the individual tower parts to handling the anchor lines for the wind turbines. Worst case loading conditions are dependent on dynamic response from the assembly platform. Current results with simulations of the complete system indicate that the pivot concept performs as anticipated. The versatility for application on different assembly platforms is yet to be proven but should result in less dynamic response and loading on both the pivot concept and turbine towers. It is clear that turbines with a smaller draught will make assembly more versatile and less sensitive to weather conditions.
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Maus, Karl Jacob & Nygaard, Tor Anders
(2009).
IEA Task 23 Offshore Code Comparison Collaborative (OC3) UMB Status September 2009 IEA Task 23 Offshore Code Comparison Collaborative (OC3) 11th Full Committee Meeting.
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Nygaard, Tor Anders & Maus, Karl Jacob
(2009).
IEA Phase IV of OC3 Offshore Floating Wind Turbine Status March 2009 IEA Annex XXIII Offshore Code Comparison Collaborative (OC3) 10th Full Committee Meeting.
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Nygaard, Tor Anders; Myhr, Anders & Maus, Karl Jacob
(2009).
A comparison of two concepts for floating wind turbines Technology and innovation track: New concepts in wind turbine and offshore technology.
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Strawn, Roger; Nygaard, Tor Anders; Dimanlig, Arsenio; Saberi, Hossein & Ormiston, Robert
(2007).
Integrated Computational Fluid and Structural Dynamics Analyses for Comprehensive Rotorcraft Analysis.
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Lim, Joon; Potsdam, Mark; Strawn, Roger; Sim, Ben & Nygaard, Tor Anders
(2006).
Blade-Vortex Interaction Prediction Using Multidisciplinary Coupling.
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Lim, Joon; Nygaard, Tor Anders; Strawn, Roger & Potsdam, Mark
(2006).
BVI Airloads Prediction Using Loose CSD/CFD Coupling.
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Nygaard, Tor Anders; Saberi, Hossein; Ormiston, Robert; Strawn, Roger & Potsdam, Mark
(2006).
CFD and CSD Coupling Algorithms and Fluid Structure Interface for Rotorcraft Aeromechanics in Steady and Transient Flight Conditions.
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Hertel, Jonas N.; Nygaard, Tor Anders & Duque, Earl P.
(2004).
Passive Pitch Control Of Small Horizontal Axis Wind Turbines.
Show summary
Finnes som IMT-trykk 11/2004
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Nygaard, Tor Anders; Dimanlig, Arsenio & Meadowcroft, E. T.
(2004).
Application of a Momentum Source Model to the RAH-66 Comanche FANTAIL.
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Nygaard, Tor Anders
(2003).
Aeromechanic Analysis of A Missile with Freely Spinning Tailfins.
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Nygaard, Tor Anders & Meakin, Robert L.
(2002).
An Aerodynamic Analysis of a Spinning Missile with Dithering Canards.
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Nygaard, Tor Anders
(2000).
Status and Prospects for Windpower in Norway.
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Nygaard, Tor Anders
(1999).
Three-Dimensional Euler Flow-Field Computations Through a Wind Turbine Rotor.
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Nygaard, Tor Anders
(2013).
Wave tank testing of Tension-Leg-Buoy (TLB) offshore wind power platforms.
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