Blar i NTNU Open på forfatter "Gao, Zhen"
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Advanced Control Algorithms to Support Automated Offshore Wind Turbine Installation
Ren, Zhengru (Doctoral theses at NTNU;2019:231, Doctoral thesis, 2019)The thesis presents the research on automated offshore wind turbine (OWT)installation. The aim of the project is to find innovative and cost-effective methods for installing and maintaining OWTs. Utilization of wind ... -
Aerodynamic Modeling of Offshore Vertical Axis Wind Turbines using the Actuator Cylinder Method
Cheng, Zhengshun; Madsen, Helge A.; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2016)Recently the interest in developing vertical axis wind turbines (VAWTs) for offshore application has been increasing. Among the aerodynamic models of VAWTs, double multi-streamtube (DMST) and actuator cylinder (AC) models ... -
An Analysis of the Impact Forces on a Jack-up Leg During Installation on Stiff Seabed Conditions
Wolfs, Céline (Master thesis, 2023)The ongoing global energy transition has led to significant growth in the offshore wind sector. This growth has resulted in a high demand for offshore installation vessels like the 'Aeolus', and the need to push up their ... -
An Analytical Model of Floating Offshore Wind Turbine Blades Considering Bending-Torsion Coupling Effect
Qu, Xiaoqi; Tang, Yougang; Gao, Zhen; Li, Yan; Liu, Liqin (Chapter, 2018)In this paper, an analytical model is proposed to describe the nonlinear vibration of blades on floating offshore wind turbine (FOWT). The bending-torsion coupling equations are derived based on Hamilton’s principle. ... -
An Integrated Dynamic Analysis Method for Simulating Installation of a Single Blade for Wind Turbines
Zhao, Yuna; Cheng, Zhengshun; Sandvik, Peter Christian; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2018)Installation of blades for wind turbines is challenging due to large lifting height and high precision. Assessment of blade dynamic responses during installation needs advanced simulation tools which are limited at present. ... -
Analysis of a Hybrid Mooring System Concept for a Semi-Submersible Wind Turbine in Intermediate Water Depth Under Operational, Extreme, and Yaw Error Conditions
Cao, Qun; Bachynski-Polic, Erin Elizabeth; Gao, Zhen; Xiao, Longfei; Cheng, Zhengshun; Liu, Mingyue (Chapter, 2022)A hybrid mooring system consisting of catenary chains and a series of clump weights was designed for the intermediate water depth, for a floating semi-submersible wind turbine. The use of multiple clump weights in the ... -
Analysis of Lifting Operation of a Monopile Considering Vessel Shielding Effects in Short-crested Waves
Li, Lin; Gao, Zhen; Moan, Torgeir (Journal article, 2016)This paper addresses numerical simulations of the lifting operation of an offshore wind turbine monopile foundation, considering both the shielding effects of the vessel and the spreading of the waves. A numerical model ... -
Analysis of lifting operation of a monopile for an offshore wind turbine considering vessel shielding effects
Li, Lin; Gao, Zhen; Moan, Torgeir; Ormberg, Harald (Journal article; Peer reviewed, 2014)This study addresses numerical simulations of the lifting operation of a monopile for an offshore wind turbine with a focus on the lowering process. A numerical model of the coupled system of the monopile and vessel is ... -
Analysis of the Parametric Instability of the STC Combined Wind and Wave Energy Concept
Appiah, Sevyllen Kistnen (Master thesis, 2017)The purpose of this study is to numerically predict such unstable motions for regular and irregular wave conditions and to compare the results with the experimental observations. First, a literature study on Mathieu ... -
Analyzing the Sensitivity of Wave Frequency Responses of Floating Vessels to Uncertain System Variables Utilizing Polynomial Chaos Expansion
Radhakrishnan, Gowtham; Leira, Bernt Johan; Gao, Zhen; Sævik, Svein; Han, Xu (Peer reviewed; Journal article, 2023)From a mathematical viewpoint, the frequency domain analysis of vessel motion responses due to wave actions is based on integration of system dynamics idealized in terms of response amplitude operators for six degrees-of-freedom ... -
Assessment of Allowable Sea States During Installation of OWT Monopiles with Shallow Penetration in the Seabed
Li, Lin; Guachamin Acero, Wilson Ivan; Gao, Zhen; Moan, Torgeir (Journal article, 2016)Installation of offshore wind turbines (OWTs) requires careful planning to reduce costs and minimize associated risks. The purpose of this paper is to present a method for assessing the allowable sea states for the initial ... -
Assessment of allowable sea states for offshore wind turbine blade installation using time-domain numerical models and considering weather forecast uncertainty
Wu, Mengning; Gao, Zhen; Zhao, Yuna (Peer reviewed; Journal article, 2022)Installation of offshore wind turbines, particularly blades, is challenging and should be executed within the allowable limit of sea states to ensure the safety and the efficiency of installation. During the execution phase ... -
Assessment of inhomogeneity in environmental conditions in a Norwegian fjord for design of floating bridges
Cheng, Zhengshun; Svangstu, Erik; Moan, Torgeir; Gao, Zhen (Peer reviewed; Journal article, 2021)Environmental conditions along a very large floating bridge are inhomogeneous due to complex topography and hydrography. Evaluating the inhomogeneity in environment conditions is important for safety design of floating ... -
Assessment of Marine Operations for Offshore Wind Turbine Installation with Emphasis on Response-Based Operational Limits
Acero, Wilson Ivan Guachamin (Doctoral theses at NTNU;2016:336, Doctoral thesis, 2016)This thesis addresses methodologies for assessment of response-based operational limits in terms of allowable vessel responses or sea state parameters, and numerical analyses of current and novel o_shore wind turbine ... -
Assessment of the Dynamic Responses and Allowable Sea States for a Novel Offshore Wind Turbine Tower and Rotor Nacelle Assembly Installation Concept Based on the Inverted Pendulum Principle
Guachamin Acero, Wilson Ivan; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2016)This paper presents a numerical study for preliminary assessment of the dynamic responses and allowable sea states for the installation of an offshore wind turbine (OWT) tower and rotor nacelle assembly (RNA) based on a ... -
Benchmarking of a computational fluid dynamics- based numerical wave tank for studying wave load effects on fixed and floating offshore structures
Nematbakhsh, Ali; Gao, Zhen; Moan, Torgeir (Journal article, 2017)A computational fluid dynamics (CFD) based numerical wave tank (NWT) is developed and verified to study wave load effects on fixed and free floating offshore structures. The model is based on solving Navier–Stokes equations ... -
Bondline thickness effects on damage tolerance of adhesive joints subjected to localized impact damages: Application to leading edge of wind turbine blades
Verma, Amrit Shankar; Vedvik, Nils Petter; Gao, Zhen; Castro, Saullo G. P.; Teuwen, Julie J. E. (Peer reviewed; Journal article, 2021)The leading edges of wind turbine blades are adhesively bonded composite sections that are susceptible to impact loads during offshore installation. The impact loads can cause localized damages at the leading edges that ... -
Broken Ice Loads on Floating Wind Turbine
Afanasjev, Mihhail (Master thesis, 2022)I interessen for å designe flytende vindturbiner for kalde områder med flytende havis, utvides det tilgjengelige tekniske verktøysettet i denne oppgaven. SIMA, en programvare for marine operasjoner og fortøyningsanalyse, ... -
Combining fully coupled analysis and linear potential theory time domain analysis to obtain cross sectional loads in the substructure of a floating offshore wind turbine
Håland, Fredrik (Master thesis, 2022)Storvolum skrog i flytende havvindturbiner har ikke en veldefinert metode for lastoverføring til strukturmodell og nye metoder trengs for å forbedre analyser. Dette studiet undersøker en ny metode for lastoverføring på ... -
Committee V.4: Offshore Renewable Energy
Gao, Zhen; Bingham, Harry B.; Ingram, Harry B.; Kolios, Athanasios; Karmakar, Debabrata; Utsunomiya, Tomoaki; Catipovic, Ivan; Colicchio, Giuseppina; Rodrigues, José Miguel; Adam, Frank; Karr, Dale G.; Fang, Chuang; Shin, Hyun-Kyoung; Slätte, Johan; Ji, Chunyan; Sheng, Wanan; Liu, Pengfei; Stoev, Lyudmil (Chapter, 2018)Concern for load analysis and structural design of offshore renewable energy devices. Attention shall be given to the interaction between the load and structural response of fixed and floating installations taking due ...