Browsing NTNU Open by Author "Gao, Zhen"
Now showing items 1-20 of 257
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A 5MW direct-drive generator for floating spar-buoy wind turbine: Drive-train dynamics
Sethuraman, Latha; Xing, Yihan; Venugopal, Vengatesan; Gao, Zhen; Mueller, Markus; Moan, Torgeir (Journal article; Peer reviewed, 2017)This article proceeds with investigations on a 5 MW direct-drive floating wind turbine system (FWTDD) that was developed in a previous study. A fully integrated land-based direct-drive wind turbine system (WTDD) was created ... -
A combined wind and wave energy-converter concept in survivalmode: Numerical and experimental study in regular waves with afocus on water entry and exit
Wan, Ling; Greco, Marilena; Lugni, Claudio; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Water entry (including slamming) and exit phenomena as well as green water on deck were observed during survivability model tests of a combined wind and wave energy converter concept. Here, a nonlinear numerical ... -
A comparative fatigue reliability study for key structural components of offshore wind turbines
Dong, Wenbin; Li, Qinyuan; Gao, Zhen; Moan, Torgeir (Chapter, 2018)In this paper, the fatigue reliability of blade root and tower base of a jacket wind turbine, the OC4 semi-submersible wind turbine and a land-based wind turbine is investigated and compared. The fatigue reliability of ... -
A comparative study of different methods for predicting the long-term extreme structural responses of the combined wind and wave energy concept semisubmersible wind energy and flap-type wave energy converter
Li, Qinyuan; Michailides, Constantine; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2018)The combined wind and wave concept semisubmersible wind energy and flap-type wave energy converter was developed in the EU FP7 project MARINA Platform. It consists of a four-column semisubmersible with a 5-MW wind turbine ... -
A comparative study on dynamic responses of spar-type floating horizontal and vertical axis wind turbines
Cheng, Zhengshun; Wang, Kai; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Interest in the exploitation of offshore wind resources using floating wind turbines has increased. Commercial development of floating horizontal axis wind turbines (FHAWTs) is emerging because of their commercial success ... -
A comparison of extreme structural responses and fatigue damage of semi-submersible type floating horizontal and vertical axis wind turbines
Cheng, Zhengshun; Madsen, Helge Aagard; Chai, Wei; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Currently development of floating wind turbines for deep water is mainly based on horizontal axis wind turbines (HAWTs). However, floating vertical axis wind turbines (VAWTs) are possible alternative due to their potential ... -
A comparison of two fully coupled codes for integrated dynamic analysis of floating vertical axis wind turbines
Koppenol, Boy; Cheng, Zhengshun; Gao, Zhen; Ferreira, Carlos Simão; Moan, Torgeir (Journal article; Peer reviewed, 2017)This paper presents a comparison of two state-of-the-art codes that are capable of modelling floating vertical axis wind turbines (VAWTs) in fully coupled time-domain simulations, being the HAWC2 by DTU and the SIMO-RIFLEX-AC ... -
A comprehensive numerical investigation of the impact behaviour of an offshore wind turbine blade due to impact loads during installation
Verma, Amrit Shankar; Vedvik, Nils Petter; Gao, Zhen (Journal article, 2019)For installing offshore wind turbines into deep waters, use of floating crane vessels is essential. One of the major challenges is their sensitivity to wave-induced vessel and crane tip motions, which can cause the impact ... -
A Crane Overload Protection Controller for Blade Lifting Operation Based on Model Predictive Control
Ren, Zhengru; Skjetne, Roger; Gao, Zhen (Journal article; Peer reviewed, 2019)Lifting is a frequently used offshore operation. In this paper, a nonlinear model predictive control (NMPC) scheme is proposed to overcome the sudden peak tension and snap loads in the lifting wires caused by lifting speed ... -
A fully coupled method for numerical modeling and dynamic analysis of floating vertical axis wind turbines
Cheng, Zhengshun; Madsen, Helge A.; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Offshore wind energy is one of the most promising renewable energy resources and an increasing interest arises to develop floating vertical axis wind turbines (VAWTs), which have the potential to reduce the cost of energy. ... -
A Global-local Damage Assessment Methodology for Impact Damage on Offshore Wind Turbine Blades during Lifting Operations
Verma, Amrit Shankar; Haselbach, Philipp Ulrich; Vedvik, Nils Petter; Gao, Zhen (Chapter, 2018)Lifting the latest generation offshore wind turbines using floating crane vessels is extremely challenging. This comes with an elevated risk of blades impacting the tower or surrounding structures due to excessive crane ... -
A Numerical Study on a Flopper Stopper for Leg Positioning of a Jack-Up Barge
Jiang, Zhiyu; Guachamin Acero, Wilson Ivan; Gao, Zhen; Li, Lin (Chapter; Peer reviewed, 2017)Jack-up barges are commonly used for marine operations in the offshore oil and gas, and offshore wind industries. A critical phase within the marine operation activities is the positioning of the jack-up legs onto the ... -
A parametric study on the final blade installation process for monopile wind turbines under rough environmental conditions
Jiang, Zhiyu; Gao, Zhen; Ren, Zhengru; Li, Ye; Duan, Lei (Journal article; Peer reviewed, 2018)Single blade installation is a method for installing wind turbine blades. If a jack-up vessel is used during an o shore installation, the wind turbine blade is mainly subjected to wind loads and experiences resonant motions, ... -
A prognostic method for fault detection in wind turbine drivetrains
Rasekhi Nejad, Amir; Odgaard, Peter Fogh; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2014)In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to ... -
A sensitivity study of wave and wind induced responses of the combined energy concept SFC based on experimental measurements
Michailides, Constantine; Gao, Zhen; Moan, Torgeir (Journal article, 2016)This paper deals with a sensitivity study of wave and wind induced responses of the combined energy concept SFC in operational and survival conditions. The sensitivity study is conducted based on experimental data. The ... -
A study on fully nonlinear wave load effects on floating wind turbine
Xu, Kun; Shao, Yanlin; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2019)The influence of fully nonlinear wave effects on floating wind turbine has been studied in this paper by comparing both floater motions and structural responses of tower base and mooring lines exposed to linear and fully ... -
A Summary of the Recent Work at NTNU on Marine Operations Related to Installation of Offshore Wind Turbines
Gao, Zhen; Verma, Amrit Shankar; Zhao, Yuna; Jiang, Zhiyu; Ren, Zhengru (Chapter, 2018)In this paper, a summary of the recent work at NTNU on the installation of offshore wind turbines using jack-up and floating vessels will be reported. The wind turbine components considered here are the monopile foundations ... -
Active heave compensation of floating wind turbine installation using a catamaran construction vessel
Ren, Zhengru; Skjetne, Roger; Verma, Amrit Shankar; Jiang, Zhiyu; Gao, Zhen; Halse, Karl Henning (Peer reviewed; Journal article, 2021)The application of floating wind turbines is limited by the high cost that increases with the water depth. Offshore installation and maintenance continue to consume a high percentage of the project budget. To improve the ... -
Active Single-Blade Installation Using Tugger Line Tension Control and Optimal Control Allocation
Ren, Zhengru; Skjetne, Roger; Jiang, Zhiyu; Gao, Zhen (Peer reviewed; Journal article, 2020)The single-blade installation is a common method for the installation of wind turbine blades. In an offshore installation, a jackup vessel is often involved, and a crane is used to lift, move, and bolt each blade onto the ... -
Active tugger line force control for single blade installation
Ren, Zhengru; Jiang, Zhiyu; Gao, Zhen; Skjetne, Roger (Journal article, 2018)Single blade installation is one of the methods for installing large wind turbine blades at an offshore site. During this installation, each blade is lifted by the main crane from the deck of an installation vessel or a ...