bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Phase-Resolved Real-Time Wave Forecasting With Unidirectional and Multidirectional Seas
Authors: Kim In-Chul , Ducrozet Guillaume , Perignon Yves 
Published: September 2023

Abstract
The development of phase-resolved real-time wave forecasting is outlined. This framework is an enhancement over previous work in that the algorithm of real-time wave prediction is extended into multidirectional seas by including the wave measurements and components in direction. However, the computations with multidirectional seas become much more numerically expensive, and hence it is often not possible to accomplish a real-time system of nonlinear ocean wave prediction. Accordingly, we suggest an improved assimilation procedure in the process of wave reconstruction, which is proven to alleviate the computational costs and establish the numerical stability of the Lagrangian approach. In addition, given an observation zone recorded by an optical sensor mounted on a fixed offshore structure, we provide a spatio-temporal prediction zone where it is suitable to obtain the prediction of the wave field by evolving the reconstructed wave information in time and space. In order to validate the phase-resolved wave forecasting, we conducted a tank-scale experimental campaign with unidirectional seas (long-crested waves) and multidirectional seas (short-crested waves). Through the comparison of model performance against the laboratory data between unidirectional and multidirectional seas, it is confirmed that the directional wave components are necessarily considered to increase model accuracy in the multidirectional case as in the unidirectional case.
Influence of Tower Design on Floating Offshore Wind Turbine Dynamics
Authors: Papi Francesco , Bianchini Alessandro , Ferri Giulio , Bruschi Niccolò , Marino Enzo 
Published: September 2023

Abstract
As research and industrial interests around FOWTs has grown, an aspect that has recently emerged is the fact that, because a floating foundation is inherently more compliant than a fixed one, in many instances tower resonance frequencies are effectively shifted upwards. While onshore wind turbine towers are typically designed with a soft-stiff approach, increasing tower natural frequencies often pushes them into or near the 3P excitation range; this aspect is exacerbated by the fact that blade-pitch controllers are often de-tuned to avoid controller-induced floater-pitch instabilities. A prudent solution to this issue is to stiffen the tower, placing the first side-side and foreaft natural frequencies above the 3P excitation, with a stiff-stiff approach. This may turn however into heavier towers, negatively influencing system stability but more importantly increasing tower base loads significantly. In this context, the current study aims at exploring the potential influence of careful tower design on FOWT dynamics and loads. The IEA 15MW RWT is used as testcase, since in its floating configuration it features a stiff-stiff tower. Four different lightweight towers are proposed. Base and top outer diameters are kept equal to 10 m and 6.5 m, whereas wall thickness and distributed structural properties vary with the height following similar patterns with respect to the fixed-bottom 15MW reference tower. The impact of these different design solutions is discussed in terms of performance, extreme and fatigue loading on the turbine and the floater. Results prove that improved and lighter tower designs may represent a key aspect to further improve FOWT design and operation.
A Report From the Drilling Riser VIV and Wellhead Fatigue JIP: Full-Scale Drilling Riser VIV Measurements and Comparisons With Predictions
Authors: Resvanis Themistocles L. , Vandiver J. Kim , McNeill Scot 
Published: September 2023

Abstract
This paper discusses some of the results and observations that were made in the Drilling Riser VIV and Wellhead Fatigue Joint Industry Project that was formed by a consortium of industry partners with the goal of studying wellhead fatigue that is caused by Vortex Induced Vibrations (VIV) of the drilling riser.
The paper focuses on presenting the field measurements of the VIV of full-scale drilling risers. The emphasis is placed on revealing the most important characteristics that need to be modelled by VIV prediction software and how modelling choices can affect the predicted VIV response. Comparisons of VIV predictions with the field measured VIV are shown and a revised set of recommended parameters is issued for use with the SHEAR7 VIV prediction program. This revised set of prediction parameters leads to less conservative response predictions on the drilling riser and lowers the wellhead fatigue. Finally, some of the challenges and limitations that exist when trying to carry out such comparisons are discussed so that future instrumentation programs can be even more fruitful.
Torque Evaluation of Cable Under Transport
Authors: Yin Decao , Mainçon Philippe , Longva Vegard , Warringa Sjoerd , Smith Carl 
Published: September 2023

Abstract
Flexible products such as power cables, flexible pipes and umbilicals may display torsion-related motion under handling, including production, load-out and installation. The torque encountered are a function of the shape of the route they follow, so routes must be designed to minimize the torques generated during handling. SINTEF Ocean evaluated the torque generated when handling cables with DEME’s cable installation & multipurpose vessel - Living Stone.
The objective of the study was to evaluate the relative magnitude of the “flip” torque induced by internal friction when the flexible product follows various routes: a proposed new concept (ConnecTT) is thus compared to the existing route on board Living Stone, and in particular, to the torques developed in a loading catenary (quayside chute to CLV chute), and the torque generated in the free span into the carousel. Both of these catenaries are inherent to any cable lay vessel, and therefore provide a good benchmark to compare results.
Scale Effect Study on the Resistance of a Double-Bow Ferryboat
Authors: Cascelli Luis Antonio Matile , Ordóñez Juan C. , Souza Jeferson Avila , Marques Crístofer Hood 
Published: September 2023

Abstract
Energy management in inland waterway transportation has become an urgent topic to address as green shipping has been receiving ever more importance from society and regulatory bodies. Since energy consumption depends on the ship’s resistance, the present work aims to simulate the sailing of a double-bow ferryboat in still water to predict accurately its resistance in model and full scale and compare the results. The numerical solution is performed with the interFoam solver, which is a standard utility to simulate multi-phase flows of incompressible, isothermal, and immiscible fluids using the Volume Of Fluid (VOF) method in OpenFOAM. Simplifying assumptions suitable to this specific problem are made, such that the incompressible Reynolds Averaged Navier-Stokes (RANS) is used herein. To close the system of equations, the SST k-ω turbulence model is employed. The numerical model is validated through experimental measurements available in the literature and then the ferryboat is simulated in both model and full scale. The resistance results for the model scale are then extrapolated to full scale and compared to the results of the full-scale simulation. Results showed that the extrapolated resistance results deviated by 8.68% on average from the full-scale simulation results.
Application of Technique for Early Consideration of Human Reliability in the Specification of the Maximum Acceptable Probability of Failure on Demand and the Maximum Spurious Operation Frequency of a Floating Nuclear Power Plant Safety Control System
Authors: Maturana Marcos Coelho , Abreu Danilo Taverna M. Pereira , Martins Marcelo Ramos 
Published: September 2023

Abstract
It is currently possible to say that there is consensus among experts that safety considerations are most effective when accounted for throughout the critical systems life cycle, starting from their conceptual design stage. However, this was not always the case and the available tools and techniques for safety evaluations were traditionally developed with the purpose of analyzing already installed systems, making it possible to identify expected failure phenomena and mechanisms just in more advanced stages of the system’s life cycle. With the evolution of the accidents studies, techniques applicable to the pre-operational phases were developed in order to reduce the risks posed by the system operation. Complementarily, as a fundamental part of risk analysis, Human Reliability Analysis (HRA) have a potential contribution for designing new systems. For this, it is essential to develop models able to feed analyzes at the conceptual design stage and to bring results that can support the decision-making. The Technique for Early Consideration of Human Reliability (TECHR) was developed for this purpose. This technique is based on the use of different sources of information to obtain probability estimates of various human error types that may occur during a specific action, and to estimate human error probabilities of generic actions. This paper presents a real application of a human performance model obtained by TECHR in specifying the maximum acceptable probability of failure on demand (PFD) and the maximum spurious operation frequency (SOF) of the Safety Control System (SCS) and of the SCS-D (a redundant system for the SCS) of a Floating Nuclear Power Plant (FNPP), incorporating the data presented in its Probabilistic Safety Assessment (PSA). This application showed the TECHR potential contribution to an SCS specification.
Probabilistic Economic Assessment of an Offshore Energy Hub Supplying Electrical Power to a Floating Production Storage and Offloading Unit
Authors: Abritta Aguiar Santos Ramon , Pavlov Alexey , Varagnolo Damiano , Børresen Børre T. 
Published: September 2023

Abstract
This paper analyzes the viability of an offshore energy hub consisting of wind turbines, batteries, fuel cells and electrolyzers connected to, and powering, an oil producing floating production storage and offloading unit. We assess these components considering an oil production setup that strives for reduced CO2 emissions. The problem is addressed from a probabilistic perspective. First, we utilize a quasirandom Monte Carlo approach to generate multiple scenarios regarding the uncertainties of the problem. Then, we evaluate the estimated net present value and total CO2 emissions of the system. As a highlight, our method is capable of exploiting a larger variety of data and capturing more sources of uncertainties compared to the literature. Open-source wind data is used to simulate wind power generation. Wind speed is modeled via a kernel density estimator to benefit the most from the data. The obtained results indicate that the renewable energy technologies enable outcomes with significant reduction to CO2 emissions. However, at the current prices of these technologies, operating a low emitting field links to the loss of a significant share of the expected profits.
Design of a Two-Body Wave Energy Converter Featuring Controllable Geometry
Authors: Tom Nathan , Ogden David , Byrne Michaela 
Published: September 2023

Abstract
While the field of wave energy has been the subject of numerical simulation, scale model testing, and precommercial project testing for decades, wave energy technologies remain in the early stages of development and must continue to prove themselves as a promising modern renewable energy field. A wave energy converter (WEC) concept currently being explored is the variable-geometry WEC (VGWEC), which aims to add an extra control option to WEC design. VGWECs attempt to incorporate controllable geometric features to adjust the floating body hydrodynamics to favor either power absorption, load shedding, or other operational goals. These variable geometry components have been proposed to be controlled on a sea-state-to-sea-state or wave-to-wave time scale depending on the force (or torque) and bandwidth limitations of the actuators required to manipulate just the controllable geometric hull features. Having control over both the WEC geometry components and the power takeoff (PTO) offers the potential to improve overall system performance and reliability if a cost-effective solution can be found for a given WEC architecture. This paper will present the recent developments and results of a VGWEC concept that incorporates variable-geometry modules into a two-body WEC. In the proposed VGWEC concept, the variable-geometry modules consist of air-inflatable bags in the surface float and a water inflatable ring in the subsurface body. The surface float is tethered directly to the subsurface body through tether lines, each connected to a separate PTO. Adjusting the geometry of both the surface and subsurface bodies along with the PTO coefficients can maximize power in design sea states while reducing motion response and PTO forces when transitioning to sea states where rated power is reached and load shedding is prioritized. The ability to transition between operating condition is expected to increase the sea state operational map and power capacity.
Offshore Oil Wells Integrity: Safety Analysis of an Offshore Oil Well at the Production Phase Using STPA (System-Theoretic Process Analysis)
Authors: Almeida Lucas Ribeiro de , Santos Joaquim Rocha dos , Pestana Marco Aurélio , Martins Marcelo Ramos 
Published: September 2023

Abstract
Despite the growing share of renewable sources, the world energy matrix still depends heavily on fossil fuels, especially oil. The exploration of this product brings severe challenges and risks which must be managed during all phases of an oil well’s lifetime. Analysis methodologies have already been developed and established to contribute to safety; however, with the growing complexity of the system, these methodologies may need a more structured way to identify some arising loss scenarios. The System-Theoretic Accident Model and Process (STAMP) deals with this problem. STAMP is a causality model that, attacking the problem from different paradigms, treats safety as a control problem, shifting emphasis from preventing failures to enforcing safety constraints. Based on a system model that spells out the control levels of a system and the control and feedback interactions between them, named SCS (Safety Control Structure), it focuses on preventing those interactions that lead the system to a hazardous condition, making it vulnerable to losses. This paper presents an analysis technique built on STAMP named System Theoretic Process Analysis (STPA), applied in the case of a submarine oil well at the production phase to highlight the benefits of using STAMP as a complement to more traditional analysis methodologies. The results conclude that STPA analysis can identify safety breaches from different sources. The first relevant source relates to the component failure events — also covered by more conventional methods such as PRA (Probabilistic Risk Assessment). The most significant contribution relates to safety breaches related to components interaction, managerial decisions, organizational factors, and others. The latter are manageable by structuring the loss scenario generation, which is the primary goal of STAMP.
CFD Investigation of the IEA Offshore 15 MW Reference Wind Turbine Performance in Full Scale: A Temporal Discretization Analysis
Authors: de Oliveira Marielle , Silva Leandro , Puraca Rodolfo , Carmo Bruno 
Published: September 2023

Abstract
A significant increase in wind turbine size was noticed in the past decade due to the expansion of the wind energy market to offshore sites, where steadier and stronger wind resources are available. This continuous rising in the wind turbines size leads to several design and manufacturing challenges. From the design perspective, the prediction of the flow behavior and wind turbine performance is a difficult task, since the use of reduced-scale experimental testing may not lead to a proper representation of the physics in the full scale. In this context, numerical simulations in full scale became a valuable tool to assist the design process and performance analysis of the wind turbine. This paper presents a Computational Fluid Dynamics (CFD) methodology to perform blade-resolved simulations of the IEA 15 MW Offshore Reference Wind Turbine to predict its performance. In this regard, a temporal discretization investigation is performed by testing three different values of Courant-Friedrichs-Lewy (CFL) number. The rotor performance is assessed when the turbine operates in optimal wind-power conversion efficiency, for a wind speed of 10 m/s at hub height. The results are compared against those obtained using the blade element momentum theory implemented in OpenFAST, in terms of power production, generated thrust, and distribution of forces along the blade span. The adequacy of each CFL number is assessed considering the computational cost and accuracy of the results in capturing the physics of the flow. Amongst the CFL numbers investigated, the results obtained with CFL = 1 and 2 presented similar behavior and satisfactory accuracy, while those obtained with CFL = 4 presented unsatisfactory results. Detailed information of the flow field in the wake internal gradient region and the flow structures that detach along the blade span were noticed using CFL = 1, while a significant reduction in the computational demand was achieved with CFL = 2. Based on the results presented, we concluded that for the cases being investigated in this paper, a good balance between accuracy and computational demand can be achieved using a CFL number equal to 2.
Study of the Influence of Microwave Irradiation on Hard Formation Property Alteration Through Nondestructive/Destructive Tests and Drilling/Coring Operations
Authors: Abugharara Abdelsalam , Mafazy Salum , Butt Stephen 
Published: September 2023

Abstract
Enhancing the Drilling Rate of Penetration (D-ROP) is a target for lowering the ultimate cost in reaching hydrocarbon reservoirs, evaluating reservoir formation, and extracting minerals and reducing rock crushing consumed energy through mining operations. It has been reported that ROP can be positively influenced depending on optimization of several factors such as drilling parameters alteration and rock fragmentation process. In this research, D-ROP is evaluated by altering the status of the formations being drilled by the use of Microwave Irradiation (MI) while all other applied parameters are kept constant. Unlike published works, this research collectively investigates the influence of MI on D-ROP of hard formation providing confirmation on rock property alteration through non-destructive tests including ultrasonic wave velocities measurement and destructive tests including Indirect Tensile Strength (ITS). Results show gradual alteration in rock properties as per MI exposure time including a reduction in P-wave and S-wave velocity, a decrease in Young’s Modulus of elasticity (E) as well as Poisson’s ratio (v). Results also show formation fractures occur when exposed to MI, which lead to a decrease in the rock strength and ultimately lead to the increase of D-ROP.
The Challenges and Opportunities for the Use of Robotic Autonomous Robotic Systems in Support of the Blue Economy
Authors: Guihen Damien 
Published: September 2023

Abstract
Economic activity in the marine environment requires the timely delivery of high-quality data that has both spatial and temporal relevance. Operation within this environment is complicated by the often-harsh working conditions that may pose a danger to staff and infrastructure. Robotic and Autonomous Systems (RAS) in the maritime domain, are increasingly seen as central to supporting the scaling-up of the blue economy.
In 2020, a scoping study on the use of RAS was conducted for the Blue Economy Cooperative Research Centre. The study involved engagement with representatives of the offshore energy and aquaculture industries, government regulators, and academics. The identified operating conditions and system roles are such that no one platform is sufficient. What is clear, however, is the need to couple more directly the efforts of platform designers, builders, and integrators with the anticipated needs of a growing stakeholder base.
The further development of technologies such as underwater communication and navigation, environmental sensing for situational awareness, power systems, and efficient and flexible autonomous logic will set the pace of RAS development. A framework for communicating operational context is proposed. This is based on the segmentation of industrial environmental conditions, assessment of the technology underpinning RAS, and the readiness of components.
Quality Assurance of Digital Twins
Authors: Eriksson Kjell , Markussen Christian 
Published: September 2023

Abstract
Digital twins, replicating the physical assets it represents, can significantly improve efficiency in the execution and operational phase. However, building robust and trustworthy digital twins that can be used for critical operational decisions, is a key industrial challenge. As a response to this challenge DNV has developed a recommended practice [1] (DNV-RP-A204) for development and assurance of digital twins. The methodology was developed in close collaboration with TechnipFMC and Aker BP and is currently being used by several leading operators and suppliers. While there are standards and commonly agreed best practices for how to assure components and systems of physical assets there is until now no common agreed standard that a digital twin can be developed, delivered, and operated according to. In the recommended practice DNV propose the following definition of a digital twin:
A digital twin is a virtual representation of a system or asset that calculates system states and makes system information available, through integrated models and data, with the purpose of providing decision support over its life cycle.
The concept of digital twins was first described by David Gelernter’s 1991 book Mirror Worlds and the term ‘digital twin’ was first coined by John Vickers of NASA in a 2010 roadmap report. The digital twin concept consists of three distinct parts: the asset, the virtual representation, and the connection between the two.
The original definitions have been included in the recommended practice, and we further propose to define the level of capability of the digital twin from descriptive, via diagnostic and predictive to fully automated solutions to increase granularity and to be able to clearly define quality assurance requirements.
The framework developed by DNV address requirements to the functionality, operations, the digital twin platform including data quality and cyber security aspects, and requirements to the organisation developing and operating a digital twin. For each of these areas clearly defined working and quality assurance processes and requirements has been defined and described.
The presentation will share the philosophy and key features of the methodology in DNV-RP-A204 as well as learnings from ongoing projects.