bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waste Heat Recovery by Binary Vapor Cycle for Gases From Marine Engines
Authors: Machado Kamille Vieira , Ordóñez Juan C. , Souza Jeferson Avila , Marques Crístofer Hood 
Published: September 2023

Abstract
The considerable energy waste in maritime transport and the need to obtain alternatives to reduce emissions of polluting gases are factors that have motivated the study of waste heat recovery systems for marine engines. The system studied herein relies on a binary vapor cycle that uses water for the topping cycle while three organic fluids were investigated for the bottoming cycle: R601a, R134a, and R22. Each of these belongs to a different category of fluid, namely dry fluid, isentropic fluid, and wet fluid, respectively. Two engines of different ratings and two different pressures of the heat recovery steam generator have been considered for each engine. Various outlet pressures for the topping turbine, which is the most liable to erosion and corrosion due to wet steam, have been investigated. The maximum efficiency achieved for the waste heat recovery system peaked at 21% while the maximum electric power accounted for 4.2% of engine brake power. Therefore, the employment of a waste heat recovery system based on a binary cycle seems a promising alternative to harnessing heat from the exhaust gases of marine engines.
A Decentralized Droop-Based Power Management System for Ship Power Systems Using Hybrid Dynamical Systems Framework
Authors: Reddy Namireddy Praveen , Skjetne Roger , Papageorgiou Dimitrios 
Published: September 2023

Abstract
In maritime transport, inspired by the automobile sector, autonomy is gaining traction in parallel with decarbonization. One of the numerous challenges in realizing fully autonomous operation in shipping is to design a resilient and fault-tolerant power system that preserves the survivability of ships during worst-case failures in unpredictable maritime weather conditions. In newly built ships, power systems are designed with a high number of sensors and communication equipment to enable remote control and condition monitoring in real time. In such power systems, the traditional concept of a centralized power management system (PMS) is not reliable during communication failures and cyberattacks. To address this issue a decentralized fault-tolerant droop-based PMS that does not rely on communication between energy sources is proposed. The droop curves are further designed for the derating operation of energy sources and energy storage devices. A ship power system exposed to faults represents a hybrid system that consists of interaction between continuous and discrete states. Hybrid dynamical systems theory is used to model the DC power system and implement the proposed PMS. The normal operation of energy sources, energy storage devices, and shiploads are modeled as continuous dynamics. The faults such as derating operation and disconnection of energy sources, energy storage devices, and shiploads are modeled as discrete events. The results demonstrate that the proposed PMS can keep the system parameters such as DC bus voltage within the limits permissible by class rules during the loss of power generation.
Influence of Propeller-Ice Loads on the Wear Development in Stern Tube Bearings of Marine Propulsion Systems and Identification of Critical Operating Conditions
Authors: Gilges Markus , Saleh Ahmed , Jain Mohit , Bekker Anriëtte , Lehmann Benjamin , Jacobs Georg 
Published: September 2023

Abstract
Increasing ship traffic in ice-covered waters leads to more frequent collisions between ship propellers and sea ice which causes extreme impulse loads on the propeller. Theses loads are transferred through the propeller shaft to the sliding bearings of the stern tube, especially, the aft stern tube bearings. Extreme bearing loads can lead to mixed-friction regimes which cause wear in the bearings and eventually results in a failure of the entire propulsion system. The effect of ice-induced loads on the contact conditions in the sliding bearings is widely unknown. Thus, a study of the influence of these loads on the contact conditions and wear behavior in stern tube bearings resulting from observed sea ice conditions and operating conditions of the ship is necessary. This paper aims to investigate the influence of ice collision loads on the contact conditions in the bearings of the stern tube of the research vessel SA Agulhas II. For this purpose, an elastohydrodynamic simulation and a multibody simulation based on field measurements were performed. As a result, this paper identifies the operating condition thresholds (i.e. propeller torque and rotational speed) during propeller-ice collisions that cause mixed-friction conditions in the bearings. On the basis of these conditions, a risk map is generated to assess the actual wear risk by including the frequency of occurrence of the corresponding mixed-friction condition over the duration of a voyage.
Roll Damping Simulations Using CFD for Offshore Wind Installation Operations
Authors: Devolder Brecht , Ramos Pedro , Stempinski Florian 
Published: September 2023

Abstract
In this work, the roll damping behavior of the offshore heavy lift DP3 installation vessel Orion from the DEME group is studied. Boundary element codes using potential flow theory require a roll damping coefficient to account for viscous effects. In this study, the roll damping coefficient is calculated using the Computational Fluid Dynamics (CFD) toolbox STAR-CCM+. Firstly, the CFD model setup is validated by performing roll decay tests and comparing the results with experimental scale model tests in a towing tank. Secondly, the roll damping is assessed by the Harmonic Excited Roll Motion (HERM) technique for various excitation frequencies and for different forward speeds. These high-fidelity full-scale simulations result in better estimations of roll damping coefficients for various conditions. This enhances the accuracy of efficient Boundary Element Methods (BEM) codes for wave-current-structure interactions simulations.
On the Digital Twin of the Ocean Cleanup Systems
Authors: Rakotonirina Andriarimina Daniel , Gonzalez Martin , Sainte-Rose Bruno 
Published: September 2023

Abstract
The Ocean Cleanup is introducing a Digital Twin (DT) describing the cleanup systems made with netted screens to concentrate marine litters and extract them from our oceans. Our DT aims at: i) avoiding over- or under-designing the system; ii) extrapolating from one system to a fleet of systems; and iii) estimating the costs of our offshore operations. These costs are evaluated as cost per kilogram of extracted plastic which is our Key Performance Indicator (KPI). One of the main contributing parameters to the KPI is the hydrodynamic load of our “U-shape” device that spans up to 630 meters and operates at a Speed Through Water (STW or ustw) up to 1.5 m/s equivalent to a twine Reynolds number of Ret* = 1600. The DT is built with OrcaFlex (OF) using lines and links, the Naumov’s drag correlation and on a no-wave assumption. Data collected from the Great Pacific Garbage Patch (GPGP) are utilised to increase the accuracy of our DT for estimating the loads and the system’s dynamic deformation. The DT is built using a three-cycle validation: i) initial guess applying the Naumov’s semi-empirical drag correlation to define OF drag coefficients which is excluding the influence of the local angles of attack (AoAs); ii) calibration of the OF drag coefficients using AquaSim (AS) with its twine-by-twine drag correlation for various AoAs; iii) re-calibration of the OF drag coefficients from two-dimensional CFD simulations using Direct Numerical Simulation (DNS) for a twine-by-twine establishment of a drag correlation on a one meter segment plane net to account for shielding effects at AoA &lt; 24°. By doing so, we decrease the discrepancy of our OF model, on large spans, with an error less than 15% compared to the GPGP data. For a narrow span, mostly exhibiting very low AoAs, the first cycle shows a 300% discrepancy whereas at the end of the third cycle it shows a 50% discrepancy.
A Numerical Investigation on the Derivation of p-y Curves for Monopile Foundations Installed in Sand
Authors: Kronemberger Lopes Guilherme , Mendes de Sousa José Renato , Cascão Ferreira de Almeida Maria , de Souza Soares de Almeida Márcio 
Published: September 2023

Abstract
The design of monopile foundations for offshore wind turbines (OWTs) is usually performed using simplified (1D) models based on the p-y method. When deriving p-y curves, the main issues arise from the soil reaction profiles (p), commonly obtained by double differentiating the bending moment profiles. Several authors have proposed modified p-y curves for OWT applications derived from experimental analysis conducted using small-scale in-situ models, centrifuge models, or numerical analysis using three-dimensional finite element (3D FE) models. This paper presents a 3D FE model simulating a monopile installed in sand, which was used to derive monotonic p-y curves. Typical curve fitting methods adopted in the literature for the bending moment data were investigated, such as the High-Order Global Polynomial, the Piecewise polynomial, the Smoothing Cubic Spline, and the single-term Fourier series methods.
Moreover, a parametric study was conducted to quantify possible errors associated with the p-y curves. The number of points used to create the p-y curve, and the number of nonlinear soil springs adopted in the 1D model were varied. Finally, a guideline for deriving p-y curves from 3D FE models is provided.
Comparison of Vessel Motion Induced-VIV Response of Lazy-Wave and W-Shaped FOWT Power Cable Configurations
Authors: Fuglsang Alex , Kusangaya Anesu J. , Dillon-Gibbons Craig , Bauer Peter , Marcollo Hayden 
Published: September 2023

Abstract
As the Floating Offshore Wind Turbine (FOWT) industry expands from demonstrator to commercial projects, arrays of FOWTs with interconnected subsea power cables will be required in order to produce a competitive Levelized Cost of Energy (LCOE). The selection of subsea power cable configuration and design of the cable networks in a FOWT array will have a significant bearing on the reliability of the power cables, the availability of power from each turbine, and the LCOE produced by the array.
Two subsea cable configurations are considered in this paper and assessed for their exposure to VIV induced fatigue damage: A lazy-wave power cable attached to the seabed, and a W-Shaped cable directly connected between two FOWTs. The model is used to compare the lazy-wave and W-shape power cable configurations; identifying the propensity of each to experience direct, heave or surge/sway induced VIV, and where detected, compares the VIV responses of the two cable configurations. The Lazy-wave configuration decouples motions of the FOWT from the subsea cable termination, but due to length of cable required to reach the seabed, may be less cost-competitive, particularly in deeper water. The W-shaped cable could reduce the length of cable required to connect each FOWT, and in a farm of potentially 100’s of floaters, may present a significant LCOE reduction. However, the W-shaped configuration may also increase exposure of the cable to multiple VIV mechanisms: Direct wave and current, heave-induced, and potentially VIV induced through the translational motions (surge/sway) of the FOWT platforms.
A Parametric Study to Enhance the Design of Hydrokinetic Turbine
Authors: Ng Cheng Yee , Maldar Nauman Riyaz , Ean Lee Woen , Wong Bak Shiiun , Kang Hooi Siang 
Published: September 2023

Abstract
Many companies and governmental organizations have announced the aspiration to achieve Net Zero Carbon Emissions by 2050. Hence, electrification and low-carbon energy solutions are among the measures to reduce CO emissions. Seeing the fact that offshore platforms are in the middle of the ocean, and the ocean covers almost 80% of the earth surface, a high hydropower potential from the ocean with 29,000 MW is extractable from Malaysia. Many of the oil and gas companies are eyeing for an alternative marine energy source for electrification of the offshore platforms such as solar, wind and wave. Unfortunately, many yet seen the potential of the marine current energy by Marine Hydrokinetic Turbine (MHKT). Indeed, the high predictability of the resources and maturity of the MHKT technology have strengthened the feasibility of the deployment of this device. Although the strength of the MHKT has been highlighted, but the deployment of the on-shelf MHKT devices in Malaysia region is still a challenge, mainly due to the slow current flow within the region. Acknowledging this limitation and insufficient depth found in Malaysian waters, the present research focusses on parametric study to maximize efficiency of an existing hydrokinetic turbine. The study is based on numerical simulations which are carried out using the CFD software. Prior to parametric study, performance of the conventional turbine is evaluated with the existing results of the manufacturer’s experimental testing reports. Thereafter, the effect of modifications on each of the structural parameters such as blade profile and number of blades arrangement is analyzed. For every structural parameter, the most optimal configuration was identified by comparing the obtained power performance variables. The enhanced design turbine achieved at the end of modifications is subjected to performance assessment for the same flow velocities as the conventional one. As a result, with the ocean current flow of 1 m/s, the enhanced design turbine can generate 268 watts of power, meanwhile 165 watts from the conventional one at the rate of 1.62 times higher.
Dynamics of a Cold Water Intaking Pipe Subject to Internal Flow and Motion Excitation
Authors: Hisamatsu Ryoya , Utsunomiya Tomoaki 
Published: September 2023

Abstract
A cold water intaking pipe/riser is an important component of a floating Ocean Thermal Energy Conversion (OTEC) plant. Its dynamics subject to the large intake flow rate of seawater and motion excitation from a platform have not been definitively understood. This study experimentally investigates the dynamics with two experimental setups. The first setup uses a controllable pump and 4 m long pipe to investigate instability. The second setup uses a high capacity pump to investigate instability and forced vibration subject to top harmonic excitation. The results are compared with an analytical model considering the inlet flow effect. The analytical model predicts that a water intake pipe does not lose stability at any high flow velocity. The experiment newly confirmed that the pipe keeps stable up to 5.5 m/s which is the maximum velocity attainable in this experiment. The experiment and analytical model also highlight that a high internal flow velocity significantly increases the amplitude of inline vibration. Furthermore, the experiment also takes a new look on the dynamics such as long-period vibration and transverse vibration.
Real-Time Automatic Prediction, Detection, and Mitigation of Fluid Loss During Drilling Operation Employing Along String Measurement (ASM) Data Along Wired Drill Pipes by Using Digital Twin in Norwegian Continental Shelf
Authors: Gomar Mostafa , Elahifar Behzad 
Published: September 2023

Abstract
To automate drilling operations, reliable real-time down-hole data, as well as knowledge to extract information about the bottom hole environment, are essential. Numerous dynamics, such as drilling bits, fluid flow, and drill string dynamics, can be employed to monitor the downhole environment. Among the many drilling parameters measured by ASM and relevant to these dynamics, fluid pressure is the key measurement, conveying valuable information regarding drilling hydraulics in real-time operations. Using ASM data, the current study uses the digital twin technique for continually monitoring downhole conditions to discern the onset and progression of fluid loss.
An authentic real-time approach for monitoring and control of downhole fluid hydraulics should incorporate both model physics and downhole measurements. An innovative physics-based data analytics model has been developed to simulate fluid flow dynamics during drilling operations. Physical models are formulated as differential equations of mass and momentum conservation, which are discretized along the borehole utilizing finite element method. As a data analytics tool, the finite element solution is integrated with Kalman filtering to estimate downhole parameters in real-time. The combination of finite element and Kalman filtering algorithms (FE-KF) offers the most efficient way of dealing with fast and continuous streams of noisy ASM data.
Using this approach in conjunction with high-frequency ASM data, flow rate and pressure along the borehole domain can be predicted in real-time. Estimates of flow rate and pressure are compared to baseline values provided by surface facilities. By identifying all contributing factors to pressure drop across the annulus, an estimate of the quantity of fluid lost can be calculated online. In this approach, a series of ASM data from a well on the Norwegian Continental Shelf (NCS) is used to identify and monitor the initiation and progression of fluid loss far in advance of detection on the surface.
Current industry solutions for monitoring downhole pressure are based on assumptions (such as mono-bore wells, simple drill strings, and Newtonian drilling fluids) that result in an unrealistic perception of the downhole environment. Furthermore, all monitoring strategies are delayed and only informative to a single point, namely the location of the pressure sensor. As a complement to such approximate solutions, these methods often make use of unreliable surface data. An intriguing aspect of this research is using digital twin to introduce an algorithm capable of overcoming the shortcomings of previous methodologies while also employing an intelligent and delicate application of ASM data to predict and mitigate downhole drilling events in real-time.
On Implementing Cummins Equation to Represent Accurate Wave Radiation Forces in Modelica
Authors: Menon Ajay , Haider Ali Shahbaz , Bubbar Kush 
Published: September 2023

Abstract
This work explores the development of a Modelica™ compliant Ocean Engineering Toolbox (OET). Focusing on a symbolic solution to the Cummins equation for a floating, heaving body subject to polychromatic wave excitation forces, three formulations of the radiation convolution (symbolic, numerical, and state-space) are investigated and validated using the benchmark WEC-Sim. The presented formulation is tested using the model parameters of the Reference Model-3 (RM3) heaving point absorber Wave Energy Converter (WEC). For a preset excitation force, a 300-second simulation of the OET yields accurate results when compared to WEC-Sim. Computational speed measurements also indicate significant improvements in simulation efficiency compared to solving the radiation convolution integral numerically.
Fluid-Structure Interaction Vibration Characteristics of Flexible Riser Transporting High-Speed Spiral Flow in Deep-Sea Mining
Authors: Zhang Jiayu , Chen Nian-Zhong , Shen Cong 
Published: September 2023

Abstract
According to Hamilton’s principle and conservation law of mass and momentum, governing equations of fluid-structure interaction and structural dynamics of a flexible riser transporting high-speed spiral flow are developed for vortex-induced vibration (VIV) analysis for lifting pipe system in deep-sea mining. The bi-directional fluid-solid interaction between flexible riser and internal and external flows is achieved by data mapping and exchange among the flow field domain and the solid domain. where the radial basis function method is used for moving interpolation of the flow field grid boundaries and internal nodes. The governing equations are then discretized and solved by the finite element method. Based on the computational fluid dynamics (CFD) method, a three-dimensional flexible riser fluid-structure coupling numerical model is established, and the numerical accuracy of the model is verified. Furthermore, dynamic characteristics of VIV of the flexible riser transporting spiral flow are investigated and the effects of internal flow velocity of the spiral flow on VIV responses are evaluated. The results show that the variation of modal vibration pattern of the flexible riser under the combined excitation of internal and external flows is evident, and the flow velocity of internal flow have significant nonlinear effects on the inherent frequency and vibration deformation of the flexible riser.
Study on the Effect of Proof Load Test on Mooring Chain Wear for Floating Structures
Authors: Takeuchi Takaaki , Kurokawa Kazuki , Hironaka Masato 
Published: September 2023

Abstract
In order to ensure the long-term integrity of floating offshore wind turbines (FOWTs), reliability assessment and cost reduction by efficient maintenance on mooring chains are part of the key issues. For achieving that, although the effect of wear and corrosion on fatigue life has been studied, only a uniform decrease in chain diameter is considered without local dimeter loss due to the interlink wear caused between links. This can lead to the unexpected early failure of the mooring chain. In order to estimate the fatigue life accurately, it is necessary to reproduce the interlink wear in the long-term.
Prior to that, the author proposed the wear estimation method and validated with short-term measurements (about 1 year). In this method, two modeling methods for coupled dynamic analysis were investigated: the conventional lumped-mass model and the 3-D rigid-body link model which is assumed to be an ideal circular configuration. However, mooring chains generally have a plastic deformation (known as the impression) at the contact part caused by the proof load test which ensures the integrity and enhances the fatigue life by loading about 70% MBS (Minimum Breaking Strength). The impression can cause the change in the rolling motion to affect the wear amount. In this paper, the wear including the rolling motion with the impression is reproduced by three-dimensional finite element analysis. As a result, it is found that the impression significantly decreases the roll-up limit angle beyond which sliding causes. Additionally, there is no significant effect of the residual stress on the wear amount.
Evaluation of Parametric Modeling Method for Ship Maneuvering Motion With Experimental Data
Authors: Zhong Yu-Xuan , Wang Zi-Hao , Zou Zao-Jian 
Published: September 2023

Abstract
Experimental evaluation is essential to the identification modeling method for ship maneuvering motion. In previous work, the authors proposed and validated a nu-Support Vector Machine (nu-SVM)-based parametric modeling strategy under noisy simulation data. In this study, the method is further evaluated and test using free-running model test data of the KVLCC2. The training dataset is selected in principle to cover the input space. The pre-processing of data, selection of model structure, and algorithm hyperparameters are analyzed and discussed. The generalizability of the identified model is tested as adequately as possible with turning circle and zigzag maneuver data that are not involved in the training process. The results show that the models trained by informative data can achieve good generalization performance despite parameter drift. The effectiveness and superiority of the proposed method are demonstrated by comparing prediction results with other modeling methods from SIMMAN Workshop, including captive model tests, RANS computation, and empirical modular modeling, etc.