Yingyi Liu

Yingyi Liu
Kyushu University | Kyudai · Research Institute for Applied Mechanics

PhD

About

46
Publications
13,502
Reads
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430
Citations
Additional affiliations
October 2015 - June 2017
Kyushu University
Position
  • PostDoc Position
September 2009 - June 2012
Dalian University of Technology
Position
  • Master's Student

Publications

Publications (46)
Article
Full-text available
This paper presents the theoretical background, the numerical implementation, and the applications of a new software that has been developed in recent years for the analysis of wave-structure interactions. The software is developed in the frequency domain, as a preprocessor of computing the wave excitation force, the added mass, and the wave radiat...
Article
Full-text available
Understanding the dynamics of an FWT (Floating Wind Turbine) is essential for its design and operation. Since a truss structure can reduce the wave load/resistance on the floating foundation, it becomes more popular in industrial applications. In this regard, knowing the effect of slender members of the truss structure on the motion response charac...
Article
Full-text available
The interaction theory presented by Kagemoto and Yue (1986) significantly reduces the computational burden in the wave interaction problem of multiple surface-piercing bodies, particularly arrays of wave energy converters in recent years. Two essential operators of the theory are the so-called Diffraction Transfer Matrix and Radiation Characteristi...
Article
Full-text available
A hybrid system integrating a power take-off (PTO) system into a floating breakwater is a promising candidate for both shoreline protection and commercial wave energy extraction. Although geometric asymmetry is important to such PTO-integrated breakwaters, its role in energy conversion efficiency and wave attenuation is poorly understood. In this s...
Conference Paper
Full-text available
You can find and download the HAMS code here: https://github.com/YingyiLiu/HAMS. I suggest you fork the entire project so that you will be able to receive the latest updates from time to time.
Article
Full-text available
In this paper, a semi-analytical model is proposed to solve the diffraction problem from a cylinder with a moonpool. The cylinder and the moonpool can be in arbitrary shapes. Linear potential flow theory and eigenfunction matching method are adopted in the analytical model. After dividing the fluid domain into three regions (i.e., the region beneat...
Article
In the multifunctional system consisting of point absorber wave energy converters and a pontoon breakwater, the breakwater plays an essential role in attenuating waves on the lee side and amplifying waves for a better energy harvesting on the stoss side. The structure of breakwater is expectedly improved to enhance its wave attenuation and amplific...
Article
Full-text available
This paper deals with a new combined concept consisting of an oscillating water column (OWC) device and an offshore wind turbine for the multi-purpose utilization of offshore renewable energy resources. The wind turbine is supported by a monopile foundation, and the attached OWC is coaxial with the foundation. Within the chamber, the exterior shell...
Article
Full-text available
The heaving wave energy converter (WEC) is one typical type of point absorber WECs with high energy conversion efficiency but significantly affected by the viscous effect. It is widely known that the bottom shape of such WECs plays an important role in influencing the viscosity, so a detailed qualitative investigation is essential. Here a numerical...
Article
Full-text available
The Green function of the diffraction-radiation theory of time-harmonic waves under a moderate water depth is considered. The paper presents a newly developed enhanced algorithm based on Endo's approach, which employs a direct Gauss-Laguerre quadrature in the calculation of the principal value integrations. This methodology was firstly originated f...
Article
Full-text available
The wave interaction with a vertical column shielded by an exterior porous shell is studied within the framework of potential flow theory. The structures are fixed rigidly at the sea bottom. The interior cylinder is impermeable, and the exterior shell is slightly porous and thin. Additionally, the exterior shell is assumed to have fine pores, and a...
Article
A plate submerged at a certain depth underneath the sea surface has been proposed as a structure type for different purposes, including motion response reduction, wave control, and wave energy harvesting. In the present study, the three-dimensional wave radiation problem is investigated in the context of the linear potential theory for a submerged...
Article
A semi-analytic model based on linear potential theory is developed to solve wave radiation from an array of truncated cylinders with arbitrary cross sections, free to oscillate independently in water of finite depth. The radiated velocity potential in the interior region below each cylinder and the exterior region extending to infinity are express...
Article
The resonant water motion inside a narrow gap between two identical fixed boxes that are in side-by-side configuration is investigated using a two-dimensional (2D) numerical wave tank based on OpenFOAM®, an open source CFD package. Gap resonance is excited by regular waves with various wave heights, ranging from linear waves to strong nonlinear wav...
Article
Full-text available
In recent years, the SPM (Single-Point Mooring) concept has been widely employed in several branches of the naval architecture and marine engineering field, such as FPSOs (Floating Production, Storage and Offloading units), offshore oil rigs, etc., but not yet popular in the offshore wind energy. To investigate the response characteristics of an SP...
Article
Full-text available
To improve the seakeeping capability, some devices, such as submerged plates, are often installed on floating structures. The attached plate can not only suppress the motion response but also provide an additional immersed body surface that receives fluid action, aggravating the wave loads. In this study, a theoretical model is developed within the...
Code
FINGREEN3D is an open-source package for computation of the free-surface Green's function under a finite water depth, which is the core-part of the boundary integral equations in the potential flow theory for analysis of wave-structure interactions. It is currently written in FORTRAN 90. The code is based on a state-of-the-art method developed in r...
Article
Tsunamis are traveling waves which are characterized by long wavelengths and large amplitudes close to the shore. Due to the transformation of tsunamis, undular bores have been frequently observed in the coastal zone and can be viewed as a sequence of solitary waves with different wave heights and different separation distances among them. In this...
Article
The infragravity (IG) period oscillations inside an elongated rectangular harbor near the offshore fringing reef induced by normal-incident bichromatic short wave groups are simulated using a fully nonlinear Boussinesq model, FUNWAVE 2.0. Based on an IG wave separation procedure, this article presents a systematical investigation on how the maximum...
Article
Full-text available
An oscillating buoy wave energy converter (WEC) integrated to an existing box-type breakwater is introduced in this study. The buoy is installed on the existing breakwater and designed to be much smaller than the breakwater in scale, aiming to reduce the construction cost of the WEC. The oscillating buoy works as a heave-type WEC in front of the br...
Article
The main purpose of this article is to systematically investigate the influence of offshore fringing reef topography on the infragravity-period harbor oscillations. The infragravity (IG) period oscillations inside an elongated harbor induced by normally-incident bichromatic wave groups are simulated using a fully nonlinear Boussinesq model, FUNWAVE...
Article
Tsunamis are traveling waves characterized by large amplitudes and long wavelengths close to the coastline. Often, the first couple of leading waves are either leading-elevation N-waves (LEN waves) or leading-depression N-waves (LDN waves). These waves are usually devastating, causing serious damage to coastal infrastructures or even human casualti...
Article
Full-text available
The present study aims to develop an efficient numerical method for computing the diffraction and radiation of water waves with horizontal long cylindrical structures, such as floating breakwaters in the coastal region, etc. A higher-order scheme is used to discretize geometry of the structure as well as the physical wave potentials. As the kernel...
Article
Full-text available
The present study aims to develop an efficient numerical method for computing the diffraction and radiation of water waves with horizontal long cylindrical structures, such as floating breakwaters. A higher-order scheme is used to discretize geometry of the structure as well as the relevant physical quantities. As the kernel of this method, Wehause...
Article
Full-text available
With the development of ocean energy exploration, reliable semi-submersible platforms with very small motion are expected to develop. Especially, in a floating offshore wind turbine system, the maximum pitching amplitude is required to be less than a few degrees. To reduce wave-induced pitch motion, a new type semi-submersible with suspensions and...
Conference Paper
The response amplitudes of different resonant modes in an elongated harbor with constant depth induced by N-waves with different amplitudes and different types are calculated using the Normal Mode Decomposition (NMD) method. Wave conditions inside the harbor are simulated with a fully nonlinear Boussinesq model FUNWAVE-TVD. It is found that, for th...
Conference Paper
Full-text available
With the development of ocean energy exploration, reliable and low cost semi-submersible platforms are expected to develop. The maximum pitching amplitude of a floater for floating offshore wind turbine should be less than a few degrees to avoid fatigue failure. In this paper, a novel conceptual design of a new type semi-submersible with suspension...
Article
Full-text available
A diffraction-radiation analysis is usually required when the hydrodynamic interactions between structural members occur in short waves. For bracings or small cylindrical members, which play important roles in the vicinity of the natural frequency of a floating platform, special care should be taken into account for the effect of viscous damping. T...
Article
Full-text available
An improved boundary element method is presented for numerical analysis of hydrodynamic behavior of marine structures. A new algorithm for numerical solution of the finite depth free-surface Green function in three dimensions is developed based on multiple series representations. The whole range of the key parameter R/h is divided into four regions...
Article
Full-text available
In this paper, a potential flow based numerical model is proposed for analysis of dynamic response of an offshore floating wind turbine system, with the consideration of hydrodynamic loads on the floating platform by the potential theory, the mooring lines by the catenary theory, and the aerodynamic loads on the wind turbine by the blade element mo...
Article
Full-text available
Hydrodynamic analysis of a moored semi-submersible type offshore wind platform has been carried out. Three methods are used in this study. The first method is the wave tank experiment with a 1/50 scale model which is carried out in the towing tank of RIAM, Kyushu University. Wind is not considered in the experiment and the mooring system is approxi...
Article
Full-text available
For the safety issue of laying and operation of submarine pipelines in deepwater oil exploitation and gas mining, the available theoretical and empirical methods were employed, besides, a relationship between the equilibrium local scour depth and the corresponding spanning length was deduced under current condition. Based on this work, an analysis...
Thesis
Full-text available
Currently, the deep-sea exploitation has entered an era of the level of a few kilometers depth, which certainly demands higher security requirements on the design and protection of the large maritime floating structures such as ocean platforms. When come to the hydrodynamic analysis and computation of these structures under the action of waves, fai...

Projects

Projects (3)
Project
Dear Colleagues and Friends, We are currently running a special issue in the Journal of Marine Science and Engineering (2020 Impact Factor: 2.033, Q2) entitled “Offshore Wind Turbine Dynamic Analysis”. The special issue is now open for manuscript submission until 31 May 2021. Manuscripts addressing new solutions and initiatives in the offshore wind sector focused on modeling, especially numerical modeling, are particularly welcomed. For further details, please follow the link to the Special Issue Website at: https://www.mdpi.com/journal/jmse/speci ... ne_dynamic Upon acceptance, the article publication charge for a regular research paper is 1800 CHF (Swiss Francs). However, note that many national and private research funding organizations and universities explicitly cover APCs for articles resulting from funded research projects. In addition, waivers are also available for authors from institutes that participate in MDPI's Institutional Open Access Program (IOAP). Please check the conditions at https://www.mdpi.com/about/ioap If you have any questions please feel free to contact me by email: liuyingyi@riam.kyushu-u.ac.jp Best regards, Dr. Yingyi Liu
Project
Dear Colleagues and Friends, We are currently running a special issue in Frontiers in Energy Research (2019 Impact Factor: 2.746) entitled “Emerging Solutions for Increasing The Market Value of Wind Energy Technology in The Energy Transition”. The special issue is now open for manuscript submission until 10 January 2021. Manuscripts addressing new solutions and initiatives in the wind sector focused on increasing its market value, from both a technological and socio-economic point of view, are welcomed. Please note that the abstract submission deadline is 29 August 2020 (only accepted abstracts will be invited for full paper submission). For further details, please follow the link to the Special Issue Website at: https://www.frontiersin.org/research-topics/15093/emerging-solutions-for-increasing-the-market-value-of-wind-energy-technology-in-the-energy-transitio Upon acceptance, the article publication charge for a regular research paper is 2490 USD. However, waivers for these fees might be possible under the Frontiers Fee Support program and also special conditions apply under the Frontiers Institutional Member. Please check the conditions at: https://www.frontiersin.org/about/publishing-fees#feesupport If you have any questions please feel free to contact me by email: javierserrano@us.es Best regards, Dr. Javier Serrano González
Project
We are pleased to release a special article issue entitled "Advances and Challenges in Ocean Wave Energy Harvesting" in the open-access journal Frontiers in Energy Research (SCIE, CiteScore=3.35, IF coming in 2020 and 2019’s value estimated to be 2.795 according to WoS). The special issue is now open for manuscript submission until the end of November 2019. Manuscripts addressing theoretical, numerical, and experimental modeling techniques in all aspects of the ocean wave energy are welcome. Please note that the abstract submission deadline is 02 August 2019 (only accepted abstract will be invited for full paper submission). Upon acceptance, the article publication charge for a regular research paper is 1900 USD. However, waivers for these fees might be possible for a high-quality paper subject to the decision of the editorial board. Visit the following link for further details: https://www.frontiersin.org/research-topics/10656/advances-and-challenges-in-ocean-wave-energy-harvesting