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Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

The impact of the wind-wave misalignment on the response of offshore support vessel in Operation andMaintenance of offshore wind turbine
Xiudi Ren1,2,3; Longbin Tao3; Martin Nuernberg4; Iman Ramzapoor3,4
1. Key Laboratory of Far-shore Wind Power Technology of Zhejiang Province. Hangzhou, Zhejiang, China.
2. PowerChina Huadong Engineering Corporation Limited. Hangzhou, Zhejiang, China.
3. Department of Naval Architecture, Ocean and Marine Engineering, University of Strathclyde, Glasgow, United Kingdom
4. Technology for Advanced Offshore Services, Edinburg, United Kingdom.

(1)

𝜙𝐼
potential(1)
𝜙𝐷
wave potential(1)
𝜙𝑅
wave potential(1)
𝜉𝑚motion(1)
𝜙𝑚mode mmand yaw𝑛𝑚
k𝑛𝑚
+
𝜙𝑖𝑗
−𝜙𝑖𝑗
potential
𝜙𝐼±
potential
𝜙𝐷±
potential

ABSTRACTWith renewable energy development, the offshore wind turbine isplaying a more critical role in ocean engineering. The operation andmaintenance (O&M) of the offshore wind turbine consumes a large
percentage of cost in the whole life of the offshore wind project. In theO&M process, the stability of the offshore support vessel whichconnecting to the wind turbine is a crucial issue. Many factors may
influence the stability of the offshore support vessels and wind turbines
during the operation period. The wind-wave misalignment, which
represents the incident angle of wind and wave, has a great impact on thestability of the offshore support vessel and offshore wind turbine. In thepresent study, the motion of the vessel and the tension along theconnecting lines are discussed under different environmental conditions.
The numerical results are validated by the full-scale measurements on
the vessel. The relative distance and tension in the mooring line arecalculated under the conditions that the wind-wave misalignment ischanging from 0° to 30°. It is found that the wind-wave misalignment
may lead to a sharp increase of relative distance and tension inconnecting lines between the offshore wind turbine and support vessels.

KEY WORDS:

Offshore wind turbine; Maintenance; Support vessel;
Wind-wave misalignment

NOMENCLATURE
Φ(𝑿, 𝑡)Φ(1) (𝑿, 𝑡)
𝜔𝜙 (1) (𝑿)potential

Complex first-order time-independent incident wave
Complex first-order time-independent diffraction
Complex first-order time-independent radiation
First-order complex amplitude of the oscillatory
First-order unit-amplitude radiation potential in
Modes referred to as surge, sway, heave, roll, pitch
Generalized normal vectors
Wavenumber
Generalized normal vectors
Sum-frequency time-independent velocity potential
Difference-frequency time-independent velocity
Second-ordertime-independentincidentwave

Second-order time-independent diffraction wave

INTRODUCTION

Total velocity potential
Total first-order velocity potential
Circular frequency of incident wave
Complex first-order time-independent total velocity

With the carbon reduction project all over the world, the offshore windenergy is becoming a new energy resource. The fixed wind turbine isapplied in the shallower water whose depth is smaller than 50m. For thewater depth larger than 50m, the floating substructure is employed withan economic consideration. Most of the offshore wind turbines are324