bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subsea Lifting Operations Considering Taut-Slack Cable Conditions and KC-Dependent Hydrodynamic Coefficients
Authors: de Andrade Emerson M. , Fernandes Antonio C. , Sales Junior Joel S. 
Published: August 2024

Abstract
The assessment of the dynamic behavior of vessel-cable-equipment systems can be complex due to the various involved parameters. For this kind of system, the practical point of view is commonly interested in maintaining the taut cable condition, avoiding the slack one. Compared to models with constant hydro-dynamic coefficients, the ones that consider Keulegan-Carpenter number (KC) dependent hydrodynamic coefficients in subsea lifting operations have different dynamical behaviors. However, there is no evidence of how the taut-slack limits change when considering KC-dependent hydrodynamic coefficients. To better understand this issue, the present study assesses three cable-equipment dynamic models with constant and KC-dependent hydrodynamic coefficients: (1) a single-degree-of-freedom, (2) a multi-degrees-of-freedom, and (3) a continuous model. Herein, we demonstrate that for a given model, at low-frequency ratios, considering KC-dependent hydrodynamic coefficients increases the region for slack in the (Λ, τ) domain, where Λ and τ stands for displacement and frequency ratios, respectively. In contrast, for high-frequency ratios, there are no significant differences. Also, we found that the taut-slack regions may differ significantly between the models, for example, surpassing a 20% difference in the frequency ratio. Furthermore, increasing the equipment mass or damping coefficients reduces the region for slack in the (Λ, τ) domain, while the opposite occurs when increasing the added mass coefficients. This study sheds light on the dynamical behavior of subsea lifting operations contrasting models with constant hydrodynamic coefficients and models considering KC-dependent hydrodynamic coefficients, showing that the response of the models may change significantly depending on the assumptions, which impacts the maintenance of taut cable conditions in subsea lifting operations.
A Digital Twin to Estimate the Remaining Fatigue Life of Risers
Authors: Mendes de Sousa Fernando Jorge , Queija de Siqueira Marcos , Kronemberger Lopes Guilherme , Gonçalves de Lacerda Thiago Ângelo , Carneiro Campello George , Figueira de Souza Rodolfo , Brun Coser Tiago , Cardoso de Almeida Ricardo , Souza de Oliveira Felipe Eduardo 
Published: August 2024

Abstract
Digital Twins can be defined as virtual models of physical systems, used to create simulations to predict the performance of equipment or processes. In offshore production systems, Digital Twins have been employed to increase operational efficiency and enhance safety. They can provide real time data to support structural integrity management decisions, such as life extension of submarine structures. The objective of this work is to present a Digital Twin application aiming to predict the remaining fatigue life of risers connected to floating production units, focusing on the top region and on tensile armors. This tool captures real-time monitored internal pressures and movement data from sensors installed on the vessels and automatically calculates the fatigue damages and remaining lives. The Riser Fatigue Digital Twin employs hybrid methods to perform global and local analyses quickly, and then calculates damage for each sea state to which the production unit and the risers are subjected. The consideration of actual measured motions at the platforms reduces uncertainties associated to traditional fatigue life evaluation methods that typically rely on vessel motions derived from Response Amplitude Operators (RAOs) and wave spectra. The presented case study illustrates the fatigue life calculation for two risers employing the proposed approach. The obtained results are compared to results referent to a simplified and traditional design method. It is expected that the Digital Twin will be very useful in providing real-time information regarding the structural integrity of the risers in operation, reducing the overall time spent on such analyses, and facilitating data-driven decision-making for integrity managers.
Uncertainty in the Extreme Waves in the North Atlantic Ocean and Ship Responses
Authors: Waseda Takuji , Sasmal Kaushik , Miratsu Rei , Kodaira Tsubasa , Zhu Tingyao , Fukui Tsutomu , Fujimoto Wataru , Ishibashi Kinya , Vukovic Vladan 
Published: August 2024

Abstract
The statistics of the waves in the North Atlantic Ocean have been used as the basis of ship design for decades. Recently, there have been efforts to update the scatter diagram of wave height and period based on the numerical hindcast data combined with AIS data. However, the validation of the extreme wave distribution is problematic due to the lack of observational data. In this study, we have compared the extreme value estimates of the wave height among a 25-year hindcast simulation and satellite-derived products from 1994 to 2018 sampled in the Global Wave Statistics areas 8, 9, 15, and 16. The comparison revealed that both epistemic and aleatory uncertainties affect the detected annual maxima (AM). Nevertheless, the difference in the estimated return period wave heights was within the statistical uncertainty. The locations and timing of the detected events can differ largely between wave hindcast and satellite observation (aleatory), and the AMs vary among satellite products for the same event (epistemic). The Atlantic wave model is based on NOAA Wave Watch III and was forced by NCEP CFSR (TodaiWW3-NK) at a relatively high horizontal (20km) and spectral resolution (10 degrees). Two curated satellite products, Ribal & Young (2019) and the CCI dataset (Dodet et al. 2020) were used.
Harnessing Uncertainty: a Generalized Polynomial Chaos Approach to Mooring Load Analysis in Offshore Floating Wind Turbines
Authors: Rafiee Ashkan , Repalle Nitin 
Published: August 2024

Abstract
This study investigates the efficacy of Generalized Polynomial Chaos (gPCE) and Bayesian Optimisation in the analysis of mooring loads for offshore floating wind turbines. Amidst inherent uncertainties, these methodologies provide robust frameworks for optimizing design and assessing mooring system fatigue. By leveraging advanced statistical techniques, the research identifies key variables influencing system performance, thereby facilitating cost-effective and resilient design strategies. The paper demonstrates the potential of gPCE and Bayesian methods to enhance predictive accuracy and streamline the optimisation process, setting a precedent for future applications in marine renewable energy systems.
Development of MMG (Maneuvering Modeling Group) Simulation Using MATLAB-Simulink
Authors: Kim Do-Kyun , Kim Jung-Hyeon , Son Hui-Hun , Choi Si-Woong , Kim Dong-Han , Yeo Chan-Young , Park Jong-Yong 
Published: August 2024

Abstract
In this paper, the Maneuvering Modeling Group (MMG) [1] model is implemented in MATLAB-Simulink [2]. By developing in MATLAB-Simulink, various variables and algorithms such as ship specifications, guidance, control, and environmental disturbances can be easily managed in block form. The similarity of the implemented model was verified by turning and zig-zag tests. Based on the developed dynamics model, various sea tests proposed by the International Maritime Organization (IMO) were automatically configured to be performed. To summarize, the results of various complex ship sea tests can be easily predicted and managed.
Geotechnical Analysis of Jack-Up Leg Mounted on Spudcan for Offshore Wind Turbines Considering Installation and Operation
Authors: Lee Min Jy , Gilo Angelica , Choo Yun Wook 
Published: August 2024

Abstract
Recently, the size of offshore wind generators and blades are increasing for more efficient energy production. Larger offshore wind turbine foundations are also required for higher vertical and lateral capacities against significant loads and bending moments. In addition, construction costs have become serious issues for developing offshore wind farms in Korea because of critical soil conditions and insufficient supply-chain for construction. Thus, the reduction of LCOE (Levelized Cost of Energy) has been highlighted in Korean market. This has obviously led to the motivation for developing a new substructure system for this purpose. This study investigates the effect of soil conditions on the foundation penetration behavior using centrifuge model tests, ISO (2016), InSafeJIP and numerical analysis using the software ABAQUS. The penetration for installation and vertical and lateral behavior for operation of the foundation was analyzed using ISO (2016), SNAME (2018) and LPile program 2013. This study showed that guidelines and test results showed quite similar penetration behavior. Additionally, lateral pile deflection of the legs will not occur significantly in this substructure, but it is necessary to check the structural stability of jack-up units.
Dynamic Simulation Procedure of Mooring System for a Floating Offshore Wind Turbine Platform
Authors: Huang Jun-Hui , Yang Shun-Han 
Published: August 2024

Abstract
Mounting a wind turbine on a floating platform allows the wind power generation more efficient and economically feasible in deeper water areas. For a floating offshore wind turbine (FOWT) system, a suitable mooring system is essential to ensure a safe and reliable operation of the entire system. However, during the design phase of a mooring system, various designs and its detailed parameters can quickly rack up the total number of simulations needed. In this study, a design procedure was proposed to capture various simulation stages and critical checkpoints for design validations of mooring systems. After identifying relevant design and evaluation parameters for the mooring system, the design procedure begins with free decay analyses and restoring performance assessments of the moored FOWT system to evaluate the intrinsic characteristics of each design candidates. In the second stage of the design workflow, 1-hr time domain simulations of the entire system were performed to eliminate design candidates that are prone to mooring slack events or any other vulnerable responses. Finally, the most suitable design of the mooring system was selected based on 3-hr simulations for the environmental conditions of 50-year return period. In the present study, design of a mooring system for the University of Maine VolturnUS-S reference platform supporting the International Energy Agency 15-MW reference wind turbine was chosen as the case study to demonstrate the proposed design procedure. The initial design matrix consists of two mooring patterns, four mooring chain diameters, and five mooring line lengths. The simulated results showed that the proposed procedure can be used as a guideline to quickly narrow down to a smaller group of feasible designs. The design process will also contribute to form the basis to develop a semi-automated mooring design tool in the future.
Development of a Simulation Performance Laboratory for Assessing DP and MASS Controllers in Complex Wave and Ice Environments
Authors: Islam Mohammed , Pearson Wayne , Gash Robert , Mills Jason 
Published: August 2024

Abstract
Activities like shipping and harvesting ocean energy are increasingly being conducted in harsh, ice-rich waters. Analytical and numerical models, validated against full-scale and model testing results, are vital to developing new technologies and understanding issues posed by operating in such environments. This paper presents the development and initial validations of a simulation performance laboratory, SPLASH, for modelling complex ice, wave and current interactions with dynamic positioning (DP) platforms and marine autonomous surface ships (MASS). SPLASH has a modular architecture, with components with well-defined interfaces tied together by a central controller. The core component is the numerical engine that models the floating system (e.g., a ship), with active propulsion and steering systems, and the complex environments, including current, waves and rigid-body ice pieces. The central controller can interface with external controllers to govern the movement of the floating system.
In the current research, two case studies were carried out: the first aimed to model and validate a complex ice-structure interaction scenario involving an ice field comprised of over 75,000 ice pieces, including brash ice, and a DP-controlled ship operating under various configurations; the second focused on modelling wave-ice-DP-ship interaction scenarios, where both regular and irregular wave are modelled in the presence of an ice field with a large number of ice pieces. The preliminary results show promise in offering a platform for accurately and efficiently assessing advanced control systems for DP/MASS operations in complex ice-wave-current environments.
Experimental Investigation of the Radiation Loads of a Heave Plate With Tilt Angle
Authors: Han Seung-Yoon , Bouscasse Benjamin , Leroy Vincent , Delacroix Sylvain , Bonnefoy Félicien , Le Touzé David 
Published: August 2024

Abstract
Installing a heave plate is a practical solution to reduce the responses of a floating system. In the case of a wind turbine, the platform is often tilted by the wind effect on the structure.
The paper presents an experimental campaign dedicated to evaluating the effect of the tilt angle on the radiation loads for a free-surface piercing circular cylinder with a circular heave plate. The horizontal and vertical loads are measured by a force transducer mounted on the bottom of a specifically designed beam. Tests in forced surge and forced heave are performed with a plate with a disk-to-column ratio of 2.9 at a single submerged draft with a draft-to-disk ratio of 0.775.
The methodology to retrieve added mass and damping from the loads measured in the tests is presented, and some results are given with a specific focus on the effect of the tilt angle on the loads. Some elements are given on how the tilt angle affects the typical hydrodynamic coefficients used in the frequency domain solvers in the presence of heave plates.
Offshore Support Structures for Green Hydrogen Systems: Overview and Perspectives
Authors: Rodriguez Claudio A. , Collu Maurizio , Brennan Feargal 
Published: August 2024

Abstract
The goals for zero-carbon sustainable industries and the demand for diverse energy matrix have triggered the research for alternative energy sources. Due to its enormous potential, ocean renewables have become the preferred choice, and several works are devoted to the study of offshore hydrogen production systems powered by offshore wind turbines. Although numerous ocean technologies are available, the choice for offshore wind turbines is a direct consequence of the maturity level of this technology without more elaborate technical criteria. The aim of the present work is to review the technologies and the state-of-the art on offshore hydrogen productions systems from a broader perspective. The design key-drivers of this system will be identified and discussed, followed by a multicriteria analysis to assess, and rank each of the available and/or promising technologies for the support structures of the offshore hydrogen production system. A strength, weaknesses, opportunities, and threats (SWOT) analysis is also provided to aid in the discussion of the challenges and opportunities for the design of offshore “green” hydrogen floating systems.
Experimental Investigation of the Influence of PDC Bit With Stinger on Drilling Performance Under Different Hole Cleaning Efficiencies
Authors: Abugharara Abdelsalam N. A. , Futheiz Ibrahim , Alwaar Abourawi , Butt Stephen D. 
Published: August 2024

Abstract
The original design of the hole opener was a stinger without a bit and was meant to guide the hole along a previously drilling pilot hole and to keep drill cuttings from falling back into the pilot hole and efficiently transport them to the surface. Later hole opener designs included and end-of-stinger bit, initially a roller cone bit and later a PDC bit. Previous research conducted at the Drilling Technology Laboratory (DTL) involved using a PDC bit at the end of the stinger for drilling experiments in both field and lab settings. These experiments revealed improved drilling performance compared to using a flat base or a passive end-of-stinger bit. Building on this research, our study focuses on drilling with a PDC bit at the stinger, but at varying distances from the base. Our aim is to examine how the distance between the stinger bit and the base bit affects drilling performance and to establish correlations that can help optimize the length of the end-of-stinger bit for optimal drilling performance. We conducted experiments drilling various types of rocks under different Weight on Bit (WOB) and Revolution Per Minute (RPM) conditions.
Experimental results indicated that drilling with and without the stinger had similar drilling performance in terms of ROP and drilling torque at low WOB. However, as WOB increased the founder point for drilling with the stinger was pushed to higher WOB and the drilling performance using the stinger was improved compared to drilling without the stinger. Drilling performance for all stinger lengths used were similar with no specific configuration performing better than the others.
A Deep Learning Method for UUV to Detect Undersea Landform Features
Authors: Xiao Yao , Huang Shuang , Wang Hongjian , Yu Dan , Chu Ling , Huang Yutong , Tian Jinmu 
Published: August 2024

Abstract
Marine topography refers to the configuration and composition of underwater landscapes, which holds significant importance for marine resource exploration and environmental research. However, conventional methods for detecting terrain and geomorphology in marine environments often struggle to accurately identify these features due to the intricate nature of the marine setting and data interference. To tackle this challenge, a proposal is made to leverage deep learning techniques for exploring ocean terrain and geomorphology. As the utilization of Side-scan Sonar (SSS) in underwater settings becomes increasingly prevalent, the study of sonar image processing is becoming more comprehensive. This study introduces a feature extraction approach for Unmanned Underwater Vehicle (UUV) SSS images based on a multi-layer feature fusion structure of a lightweight Fully Convolutional Network (FCN). The method aims to address issues such as low precision in feature extraction, inadequate boundary coherence, and suboptimal edge detail in existing methods for extracting features from SSS images. Recognizing the abundance of convolution parameters in the fully connected layer leading to network model complexity and information loss, a lightweight FCN is devised to reduce computational load, simplify the network model, and prevent information loss due to large dimension spans. Experimental findings demonstrate that this method not only ensures adequate network training but also leverages information correlation across different convolution layers to enhance the network’s ability to capture and fuse effective feature information, thereby improving the integrity of feature extraction edges in SSS images.
Hydrokinetic Energy Harnessing Using Two Tandem Cylinders With Large Turbulence Stimulation and Nonlinear Damping in Flow-Induced Oscillations
Authors: Congpuong Nipit , Sadiq Salman , Sun Hai , Bernitsas Michael M. 
Published: August 2024

Abstract
Large Passive Turbulence Control (PTC) and nonlinear adaptive damping are used together to improve the efficiency and power-to-volume ratio of the VIVACE converter at the Marine Renewable Energy Laboratory (MRELab) of the University of Michigan. A large PTC is attached to two cylinders in tandem. Linear damping is used on the upstream cylinder and adaptive damping on the downstream cylinder. With this configuration, the flow-induced oscillation (FIO) of the leading cylinder starts at water speed of 0.36 m/s. FIO initiates as linear resonance leading to VIV. Then VIV and galloping coexist until a water speed of 0.9 m/s before reaching pure galloping with no gap in FIO. The mechanical power of each cylinder is calculated based on experimental measurements. The combined mechanical power of the two cylinders increases quadratically with the flow speed. This new PTC along with adaptive damping modify the efficiency curve to be maximum over the range of water speed between 0.5 and 0.9 m/s regardless of stiffness and damping. This extension of the optimal efficiency to a wider flow speed range allows the converter to work well in real environment where the water flow has nonuniform speed.
Influence of Wave Spreading on Offshore Wind Turbine Design: a Monopile Supported DTU 10-MW Turbine Case Study
Authors: Ryan Gerard V. , McAdam Ross A. , Adcock Thomas A. A. 
Published: August 2024

Abstract
Offshore ocean waves are directionally spread, whereby the propagation of energy travels in different directions. Despite this multi-directionality, the use of 3-dimensional wave models for loading on fixed offshore wind turbines has been limited. This is partially due to the common assumption that uni-directional sea states are conservative within a design philosophy. This may not always be true given that in operating conditions the amount of aerodynamic damping in the side-side direction is much lower than the fore-aft direction.
This paper aims to address this issue by providing the influence of wave spreading on various offshore wind turbine design scenarios: fatigue, ultimate and service limit state design. This study demonstrates that wave spreading indeed results in more fatigue damage for operating load cases. Despite this increase in operating cases, the overall fatigue and ultimate limit state utilisation is still reduced when a wave spreading is adopted.
Analytical and Numerical Modeling of the Wall Scraper for Horizontal Wells
Authors: Gao Xiang , Hao Xiao , Zhou Mengmeng , Song Xianzhi , Yuan Guohai , Xu Zhengming , Zhu Zhaopeng , Qi Yiqun , Jiang Dan 
Published: August 2024

Abstract
Horizontal wells are being widely used with the increase of oil and gas demand and the development of extraction technology. During the drilling process of horizontal wells, cuttings are easily deposited on the bottom of the annulus to form cuttings bed due to the gravity, which may lead to safety accidents, such as, high friction and high torque, and pipe sticking. In recent years, downhole tools have been innovatively proposed to use to improve the hole cleaning efficient. There are many factors that affect the effectiveness of the downhole tools. This paper establish the model of the wall scraper and utilizes a Computational Fluid Dynamics (CFD) to obtain hole cleaning efficiency with different parameters. The simulations were conducted at steady state and the results for maximum cutting concentrations in the annulus were analyzed. The results shows that the flow rate, drillpipe rotation speed, cuttings size, and cuttings concentration have significant impact on cuttings transport. This study could provide theoretical support for the subsequent development and application of downhole tools.