bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrodynamic Damping of a Circular Cylinder in Current With High-Frequency In-Line Oscillation
Authors: Pang Dan , Cheng Liang , Jiang Hongyi , Tong Feifei , An Hongwei 
Published: September 2023

Abstract
This paper investigates the hydrodynamic damping of an oscillating circular cylinder in a steady current. The standard approach for estimating the hydrodynamic loads from combined wave and current conditions on structures employs linear superposition of the loads induced by each component separately. To validate the linear superposition assumption, two dimensional (2D) direct numerical simulations (DNS) of an oscillating circular cylinder in current have been carried out at Rec = 47–600, high Stokes number (β = 1000) and low Keulegan-Carpenter number (KC = 0.001–2).
The drag force and the inertia force are decomposed by assuming that the drag component is in phase with velocity profile, while the inertia force is out of phase by 90°. The performance of two hydrodynamic models in existing design guidelines, the relative velocity model and independent velocity model, have been examined under the parameter range in this work. The results show that the independent velocity model outperforms the relative velocity model in predicting hydrodynamic damping.
Experimentally Determined Response Behavior due to Waves for a Loitering Remotely Operated Vehicle Near the Surface
Authors: Marks Johnathan D. , Klamo Joseph T. 
Published: September 2023

Abstract
The objective of this research was to quantify the undesired pitch and heave motions caused by wave-induced loads on an ROV operating near the surface. An experimental study was conducted utilizing a towing tank with wave making capability and a commercially available ROV, the Blue Robotics BlueROV2. The ROV was tested in the tank, near the water surface, at zero forward speed in both single-component and two-component wave fields. Pitch, depth, and thrust data were collected from the ROV and compared against control runs to determine the effect of the wave-induced loads on the pitch response of the ROV and its ability to maintain depth. For pitch, the results showed that the response had components that were caused by linear wave loads and nonlinear wave loads. The linear loads resulted in a pitch response that increased with wavelength. Low-frequency nonlinear loads resulted in a measurable pitch response when the frequency difference was near the system natural frequency. For depth, little response was seen due to the control authority of the ROV. However, the vertical thrust response showed that wave-induced loads have the potential to affect depth if sufficient control authority is not present.
Subsea Processing Optimization Considering Reliability and Maintenance
Authors: Sales Leonardo , Stolpnes Thomas , Stanko Milan , Faanes Audun 
Published: September 2023

Abstract
Subsea technology often enables the low-cost development of small marginal fields with short production lifetimes and low profit margins. However, ensuring high levels of reliability and low maintenance requirements for these subsea systems is critical for success and can be difficult to achieve. The goal of this research is to use numerical programming and optimization as a decision-support tool for the design of subsea production systems, while taking reliability and maintenance into account.
The optimization was designed to determine the most suitable subsea equipment and production strategy while considering production constraints, system downtime, lost revenue from production losses, and operational expenses. The reliability and maintenance model was integrated in the optimization model to provide the best solution possible, avoiding the problem of using two separate models that may only provide suboptimal results. This paper also discusses some of the difficulties in offshore reliability and maintenance modelling, as well as the uncertainties, constraints, and calculations used to improve the model’s accuracy.
The method was tested on a synthetic field study case in the Norwegian Continental Shelf. When reliability and maintenance parameters were included in the model, a different optimal solution was discovered. When the two solutions were compared, the new optimal design had an increase in NPV of 11 million USD over the previous one. The methodology presented advances modelling and automated decision-making in subsea production system design.
Hydrodynamic Modelling of Membrane Floats Floating PV System in Offshore Environments
Authors: Taneli Marvin Ananda , Bakti Farid Putra 
Published: September 2023

Abstract
In this study, the hydrodynamic responses of Membrane Floats Floating PV System in offshore environments were studied. The structure is modelled based on previous experiment of multi-tori structure by Jonathan Winsvold in 2018. The experiment significantly simplifies a complex membrane structure into sets of tori and truss structures, which were much easier to handle in both experiment and in numerical settings. Just like the Winsvold (2018) experiment, the continuous membrane is modelled as five discrete elastic tori that are connected by elastic trusses in the radial direction. The elastic truss elements have negligible inertia properties and their tension are configured to mimic the actual membrane stiffness. The experimental scale numerical model is validated against the experiment and theoretical results from literatures. Then, the full-scale structural diameter of 50 metres and torus cross-sectional diameter of 1.6 metres is modelled in the numerical setup. In this study, the load from Solar PV Modules were inserted as additional mass per length on the tori to better represent the real-world condition. To obtain better understanding of the hydrodynamic behavior of the membrane floats, two configurations of wire rope mooring systems and various membrane pre-tensions were simulated in the time domain. The mooring response and elastic behavior of the structure under various environmental load such as current and wave were also investigated. The wind loading is neglected in the present study, considering that the FPV has almost zero elevation. The sensitivity study results were then presented in the frequency domain. The simulation results suggested that mooring configuration significantly affected the structural response of the outermost part of the membrane, while has little to no effect on the innermost part of the membrane. The membrane’s sensitivity to the change in elongation (i.e., pre-tension) shows that the model were also able to capture the increase of the membrane’s apparent bending stiffness. Based on the results, the model may be used to provide further insight to improve future design of the membrane floats floating PV systems. The approach also opens up the possibilities of using a typical, more accessible, off-the-shelf rod or beam element-based FEM software to be used for simulating membrane type FPVs.
Sloshing Loads Estimation Using a Genetic Programming
Authors: Ahn Yangjun 
Published: September 2023

Abstract
Genetic programming (GP) is used to analyze the sloshing loads in a rectangular tank. The solution of the GP has been validated through a series of model tests of harmonic and horizontal excitations in a range covering all technically possible frequencies. The model tank scale is 1/40. The liquid depths are 70% and 95% of the tank height. 90 piezo-electric sensors are installed to measure pressure time signals for 200 cycles of excitation. Three different density ratios between the ambient air and liquid are considered. The genetic algorithm is to find an optimum solution for the average of the ten largest peak pressures for different frequencies. It considers the different loading conditions, density ratios of the ambient air and liquid, and excitation frequencies. The genetic algorithm is extensively validated for different population initialization, selection algorithms, crossover algorithms, mutation algorithms, and replacement algorithms. Good agreement is shown for the attributes leading to the optimum formulation of the sloshing loads. The solution of GP provides a simple and fast estimation of the sloshing loads. Furthermore, this application shows potential for practical application of analyzing general sloshing loads of various environmental conditions that the vessel would experience.
Effect of Axial Compression on Flexural Strength of Freshwater Ice
Authors: Anwar Taha , Taylor Rocky , Wang Jungyong 
Published: September 2023

Abstract
In the design of bridges, wind turbine towers, offshore structures and ice-class ships for operations in ice-prone regions, sloped structures may be employed to promote flexural failure of level ice to reduce loads on the structure. During such interactions, the ice sheet does not fail in pure bending since a component of the applied force at the sloped interface results in an axial load that induces a compressive stress in the ice. The net effect of this axial component is that the corresponding compressive stresses balance with flexure-induced tensile stresses in the outmost fibres of the ice. As a result, the apparent flexural strength of the ice is expected to increase with increasing axial compression, since larger bending forces would be required to generate sufficient tension to trigger fracture. In ice load prediction models for sloped structures, an in-plane compression (IPC) factor is applied to calculated loads to account for increased flexural strength which is empirically determined to be 1.5. While the method of superposition may be used to assess combined loading effects for elastic structures, assessing such effects in ice is more complex since the behaviour of ice is not purely elastic. In this paper, the relationship between axial compression and the flexural strength of freshwater ice is studied experimentally to assess how the flexural failure behaviour of the ice changes for different levels of in-plane compression factor. A series of experiments on freshwater ice have been conducted for compression levels at 75%, 135% and 185% of unconfined flexural strength for ram speeds of 0.1 mm/s, 1.0 mm/s and 10.0 mm/s. These results indicate that in-plane compression significantly increases the apparent flexural strength of the ice, highlighting the need for further work in this area to better understand this phenomenon and assess implications for design. This new testing approach provides a promising direction for further examination of these important effects, including extending this work to the analysis to sea ice and to consider lower IPC values.
Cross-Domain Knowledge Discovery and Sharing in Digital Subsurface Based on Federated Learning
Authors: Zhang Nan , Liu Ye , Geng Jiahui , Cui Boyu , Seo Jungwon , Cao Jie , Rong Chunming 
Published: September 2023

Abstract
The total volume of data in the subsurface is tremendous and grows exponentially each year. Sufficiently and effectively utilizing the subsurface data from multiple sites will advance the knowledge required for innovations that power the future growth of the energy industry. This research article explores the increasing needs and challenges for cross-domain knowledge discovery and sharing in the digital subsurface, and demonstrates the application of federated learning for improving the generalization ability and prediction accuracy of machine learning models using Rate of Penetration prediction as a field case study.
The lack of effective privacy and ownership protection solutions restricts the effective utilization of subsurface data across different organizations. However, due to the significant geological heterogeneity in reservoir formations and the severe long-tailed distribution, the machine learning models trained from a single data site suffer from overfitting and weak generalization ability. Federated learning provides a possible solution for this dilemma by training machine learning algorithms from multiple client datasets without exposing the data. Following the client-server architecture, clients train local models on their local datasets and exchange parameters with the central server at some frequency to generate and improve the global model.
In this paper, we demonstrate the application of federated learning for knowledge discovery and sharing across multiple sites using field data from multiple resources to train an advanced Long Short-Term Memory (LSTM) artificial neural network for drilling Rate of Penetration prediction. We discuss the learning and predictive performance of the global model, which outperforms local models in generalization ability and prediction accuracy due to the additional datasets contributing to revealing the actual data distribution. While this study provides promising results, potential limitations of this approach in the energy industry are also discussed.
Numerical Assessment of Novel Ice Breaking Technology
Authors: Tabri Kristjan , Saar Kalju , Aanensen Marie , Andersen Steiner 
Published: September 2023

Abstract
Paper deals with numerical assessment of a detachable icebreaking bow, that uses novel ice breaking technology. With the new technology, significantly smaller vessels are required for the ice breaking and the ice breaking capacity is exploited only when necessary. This is achieved by conceptually new ice breaking mechanism, where the ice is broken under 3-point bending mechanism. The focus is on ice fields with the maximum ice thickness up to 0.9 m.
Analytical and Finite Element Models for the Analysis of a Hybrid Flexible Pipe Under Combined Axisymmetric Loading
Authors: Freitas Inês S. G. , De Sousa Jose Renato Mendes 
Published: September 2023

Abstract
Hybrid flexible pipes, consisting of typical flexible pipes with composite layers replacing steel armors, are an alternative to traditional flexible pipes because they are lighter and insensitive to Stress Corrosion Cracking (SCC). Hence, the present work proposes analytical and finite element (FE) models for analyzing the behavior of offshore hybrid flexible pipes under combined axisymmetric loads, such as axial force, torsion, and internal and external pressure. The analytical models were implemented in Matlab and relied on equilibrium and compatibility equations combined with the Classical Laminate Theory (CLT) and the Lamé theory, representing the composite and the other non-composite polymeric layers. In contrast, the FE models were constructed in ANSYS®, where three-dimensional solid elements modeled the layers of the pipe, and contact elements ensured their interaction. Finally, a case study compared their responses, revealing an excellent adherence between the proposed models. Moreover, some insights concerning the orientation of the plies in the composite layer are presented and indicate the importance of associating different fiber orientations because risers are subject to complex load combinations.
Dual Shear Gun for Efficient Drilling Fluid Shearing – Laboratory Experiments
Authors: Taghipour Ali , Lund Bjørnar , Ytrehus Jan David , Saasen Arild , Ånesbug Geir Olav , Pallin Jan Egil 
Published: September 2023

Abstract
A dual shear gun prototype was produced to provide an efficient, low noise shear gun for rig site shearing of oil-based drilling fluids. At the same time this shear gun shall not produce metallic debris to the drilling fluid as such debris alters logging results. In this shear gun, two opposite directed jets collide inside a silencer chamber. Improved efficiency of the shear gun reduces the need for drilling fluid circulation to maintain drilling fluid properties.
Initial series of laboratory experiments are conducted. During the experiments a pumping unit was connected to a fluid tank and a divided flow is lead through a model shear gun device with adjustable nozzles. The viscosity and electric stability were measured as a function of time for the mixture. The experiments were conducted in an acrylic model of the planned tool. It is also possible to implement camera recordings of the experiments, including borescope view from the centre of the mixing unit.
Within the accuracy of measurements, also following API specifications, the viscosity profile developed rapidly. No significant noise was observed from the shear gun. These two properties are showing that the shear gun will be efficient in practical application. An analysis shows how the dual jet mixing chamber flow appears and how this flow will provide proper mixing.
Wave Effects on Vortex-Induced Motions of a Floating Offshore Wind Turbine
Authors: Passano Elizabeth , Yin Decao 
Published: September 2023

Abstract
Vortex-induced motions (VIM) of a spar type floating offshore wind turbine (FOWT) are studied. Wave effects on VIM responses are discussed and investigated using nonlinear time domain numerical simulations with typical combinations of current and waves.
VIM displacement orbits are sensitive to the ratio between the in-line and cross-flow natural frequencies, which is determined by the nonlinear stiffness introduced by the mooring system.
The simulations show that the waves reduce the VIM responses. This is in agreement with findings from VIM model test of other systems. The reduction is larger when the waves are in the cross-flow direction than when the waves and current are in the same direction.
Mean and dynamic tension forces are checked and cross-compared.
Latching Control of Wave Energy Converters Using Tunable Electrical Load
Authors: Tahir Uzair Bin , Zhang Jingxin , Manasseh Richard 
Published: September 2023

Abstract
Frequency of ocean waves varies over the time, and maximum power generation is only possible when wave energy converters (WECs) and incoming waves are at resonance. Adaptive control strategy is required for an optimal power absorption, which is impractical using available mechanical models. Electrical load control strategy can help to achieve the resonance condition without any structural change. WEC studied in this paper is a heaving bouy connected to the electrical power take off (PTO) having tunable passive load at the output. Electrical load based compensation has been presented to achieve the resonance during varying ocean wave frequencies. Many control strategies have been investigated in the past, but always required complex mechanical and electrical implementation. The only notable electrical control strategy is complex conjugate match, which is misleading as it requires external power to be implemented. Mechanical latching control is known for decades that can provide optimal tuning of excitation wave with WEC device for maximum power absorption. Electrical load based latching control has been used which regulates movement of the bouy according to the input wave force. An electromechanical mathematical model has been presented for the control conditions, and MATLAB/Simulink is used for the simulation of WEC’s operation under regular input waves. Results shows the use of passive electrical damping can control velocity, displacement, and improve power absorption compared to conventional latching control.
Preliminary Assessment of the Effect of Bottom Warp on the Dynamics of Planing Hulls Using OpenFOAM
Authors: Paredes Rubén J. , Plaza David , Marin-Lopez Jose R. , Begovic Ermina , Datla Raju 
Published: September 2023

Abstract
The prediction of the dynamics of High-Speed Craft (HSC) with prismatic hulls is commonly performed by designers using semi-empirical formulations based on Savitsky’s classic method. However, the accuracy of this prediction decreases with the presence of warp, when the deadrise of the hull change along its length, which is typical for small passenger ferries, even when considering the effective deadrise and trim angle concept proposed by Savitsky in 2012. The present work assessed the dynamics of three planing warped hulls and one prismatic monohull developed by the University of Naples, using a morphing grid approach implemented in OpenFOAM to capture the motion of the vessel. Numerical results on resistance, wetted area, dynamic trim angle, wall shear stress, and pressure distribution were compared with the method proposed by Savitsky, and previously published results where possible. Results suggested that it is possible to improve Savitsky prediction by changing the location where the equivalent deadrise angle is evaluated. This single modification will allow to extend the application of Savitsky method for a wider range of warp rates.
The Coupling Effects of Bubble Collapse, Ice Breaking and Structural Response
Authors: Chen Qiyang , Xiong Chengwang , Dong Qianqian 
Published: September 2023

Abstract
This study is concerned with the coupling effects between the fracture of an ice plate floating on the water surface induced by the pulsation of a high-pressure bubble and the corresponding deformation of an aluminium plate that is obliquely connected to the horizontal plate. The dynamic behaviours of bubbles and fractured ice were captured by high-speed cameras, and the transient plastic deformation of the aluminium plate was analysed with a digital image correlation (DIC) system. Our experimental observations revealed that the jet direction of the collapsed bubble strongly depends on the thickness of the ice, since the fractured ice causes an abrupt change in the boundary condition. It is notable that the jet direction was also influenced by the angle of the two walls and the standoff distances of the bubble. The angle of the ice and aluminium plates determines whether the jet points towards the corner or the walls. The location with the smallest bubble-ice distance and the largest bubble-plate distance generally provided the strongest ice-breaking capability due to the vertical jet impact by bubble collapse. However, a small bubble-plate distance should be avoided to prevent the deformation of the aluminum plate. The study can shed light on the efficient and safe ice-breaking strategy by understanding the dynamics of bubble collapse near floating ice and structures.
Lateral Buckling of Tensile Armor Wires in Flexible Pipe Subject to Axial Compressive and Cyclic Bending Load
Authors: Ye Naiquan , Ji Guomin , Sævik Svein 
Published: September 2023

Abstract
Flexible pipes and subsea cables are often manufactured with a number of helically wound armor wire layers. Lateral buckling of tensile armor wire may occur when the flexible pipe is exposed to combined axial compressive load and cyclic bending. During installation and operation in hash offshore environments, the touch down section of the flexible pipe may subjected to compressive axial load together with cyclic bending, which can lead to severe damage to the flexible pipe due to the lateral buckling failure mode. The present study investigates the lateral buckling capacity of one 8” flexible riser using Repeated Unit Cell (RUC) modelling technique. The RUC model has been proven to be valid in predicting the onset of the material yield in the most vulnerable tensile layer by comparing the results with a full-scale test data. Development of the stress components in the tensile amor wires as a function of cyclic bending, distribution of gaps between tensile armor wires around circular position are discussed. Lateral buckling is assumed to occur when the total axial stress exceeds yield stress of the armor material. Lateral buckling capacity is defined as the ability of the cross section to withstand certain amount of axial compression when it is exposed to a certain number of cyclic bending.