bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reconstructing Sea-States in the Southern Ocean Using Ship Motion Data
Authors: Nelli Filippo , Van Zuydam Armand , Pferdekamper Karl , Alberello Alberto , Derkani Marzieh , Bekker Anriëtte , Toffoli Alessandro 
Published: October 2021

Abstract
Sea state conditions can be estimated from the motion of a moving ship by converting its response to incident waves through the response amplitude operator. The method is applied herein to ship motion data from the icebreaker R/V Akademik Tryoshnikov and recorded during the Antarctic Circumnavigation Expedition across the Southern Ocean during the Austral summer 2016–17. The response amplitude operator of the vessel was estimated using two boundary element method models, namely NEMOH and HydroSTAR. An inter-comparison of model performance is discussed. The accuracy of the reconstructed sea states is assessed against concurrent measurements of the wave energy spectrum, which were acquired during the expedition with the marine radar WaMoS-II. Results show good agreement between reconstructed sea states (wave spectrum as well as integrated parameters) and direct observations. Model performances are consistent. Nevertheless, NEMOH produces slightly more accurate wave parameters when quantitatively compared against HydroSTAR.
Flow Characteristics of Foam in Fractures and Prediction of Preferred Paths
Authors: Xu Zhengxiao , Li Zhaomin , Li Binfei , Chen Danqi , Zeng Xianghui , Wei Yao , Ji Changfang 
Published: October 2021

Abstract
Foam is widely used in fractured reservoirs. The flow characteristics in complex fracture networks are still unclear, and there are few numerical simulations of foam fluid flow in fractures. In this study, a variety of combined visual fracture models were used to observe the flow characteristics of foam in the fracture. Firstly, based on the parallel fracture model, the foam flow characteristics under different fracture depths were explored, and then based on the complex fracture network model, the foam flow path and sweep efficiency are evaluated. Finally, the Dijkstra’s algorithm was used to determine the weighted graph of the fracture network nodes, and the preferred flow paths of the foam were predicted. The results show that when foam flows in parallel fractures with different depths, it preferentially flows in high permeability (100 μm) fractures, and there is gas trapping in low permeability (50 μm) fractures. In the irregular fracture network model, the sweep efficiency of the foam fluid is greatly affected by the foam quality, and the sweep volume is the widest when the foam quality is about 90%. The simulation results based on the Dijkstra’s algorithm can be fitted to the experimental results to a certain extent. By controlling the number of preferred paths and the weight of nodes, the plugging and regulating performance of the foam are characterized. These findings reflect the necessity of considering fractures when foam flows in reservoirs, and provide a certain experimental basis and theoretical guidance for the development of fractured reservoirs.
Determination of Hydrodynamic Masses and Roll Periods of Ships in Shallow Water
Authors: Jannsen Larissa , Krüger Stefan 
Published: October 2021

Abstract
Due to the fast increase of the vessels’ size over the past few years the actual water depth is becoming more and more relevant for seakeeping problems. The highly frequented sea route TSS Terschelling – German Bight for example is a shallow water route for large vessels which are now affected by the reduced keel clearance. Many shallow water depth areas occur also in coastal areas or inland seas. If a vessel is travelling in shallow water sea states, the hydrodynamic forces will change compared to deep water sea states and they are essential for further seaway calculations. Furthermore, a rough but easy evaluation of the incoming seaway is the roll period. Shallow water effects should be taken into account for calculating roll periods and thereby predicting a manageable or risky seaway situation. This paper presents the implementation of shallow water effects into an existing 2D panel code. With this panel code the hydrodynamic forces for the vessel’s frames are calculated based on the potential theory in the frequency domain, which is a validated approach in the early design stage. The panel code is part of the ship design environment E4 which is being developed by the Institute of Ship Design and Ship Safety, among others. With the expanded method it is possible to calculate hydrodynamic forces also in shallow water in all degrees of freedom. Therefore, the frame motions are converted to global ship motions. Furthermore, for the usage in the early design stage the calculations should be fast but also accurate. The obtained calculation results are therefore validated with full scale measurement using Inertial-Measurement-Units.
Development and Testing of Bridle Line Power Generation for Aquaculture
Authors: Grehan Patrick , Casey Conor , McEvoy Paul , Wann Annicka 
Published: October 2021

Abstract
This paper presents the development and testing of Gator, a hydraulic Power Take Off (PTO) being commercialised for the Aquaculture market. Gator uses a novel polymer bellows to pump pressurised water through a power take off system, while also providing a non-linear force response that reduces mooring line loads over traditional mooring lines.
The Gator system is comprised of 4 distinct subsystems: The Gator pump, hydraulics, turbine, and electrical storage & control. The Gator pump is a polymer component that compresses under load, pumping water through check valves into the hydraulic system. The connected hydraulic system takes the pressurised water, regulates the pressure and flow rates with an accumulator, and provides a steady flow of water to the turbine, generating electricity.
This paper will provide an overview of the technical development of the Gator system over several phases, which has focussed its adaptation for use in the aquaculture industry as an inline pump on cage mooring lines.
A description of comprehensive testing undertaken on a linear test rig to simulate the variable loading that the system would experience in operation will be provided as well as some of the early characterisation results from this testing.
Digital Twin of a Maneuvering Ship: Real-Time Estimation of Derivatives and Resistance Coefficient Based on Motion Sensor
Authors: Uehara Sasaki Humberto A. , Ianagui André S. Sandes , Cardozo de Mello Pedro , Tannuri Eduardo Aoun 
Published: October 2021

Abstract
Retrieving certain hydrodynamics coefficients from a marine craft during a maneuver can be useful for various reasons, such as the validation of project specifications or the rapid verification of structural changes that could impact the vessel movement. Intended to estimate some of these parameters, the present work proposes a method purely based on traditional Extended Kalman Filter (EKF) focused for limited drift angles.
Albeit not posing as a replacement to conventional estimations, such as from Computer Fluid Dynamics (CFD) — which solve equations in order of millions — and experimental tests — with its time-consuming preparation setups and post-analyses — the method can possibly present itself as a convenient and quicky technique to estimate the hydrodynamics coefficients in real time, as each iteration resorts only into a few dozen of equations.
Preliminary results in the simulated environment called pyDyna — a python version of the Numerical Offshore Tank ship maneuvering simulator — indicate this procedure is faster along with an acceptable margin of accuracy, possibly pointing as a feature for future digital twin applications.
Translational Periodic CFD Model: A Practical Solution to Capture Hydrodynamic Slugging in Horizontal Pipes
Authors: Agrawal Madhusuden , Khanna Samir , Kopliku Ardjan , Lockett Timothy 
Published: October 2021

Abstract
Prediction of erosion rate, flow-induced vibrations and fatigue assessment depends strongly on the way multiphase flow occurs through fittings such as bends, tees, manifolds, etc. Therefore, it is important to have a better understanding of multiphase flow behavior to improve confidence on erosion and fatigue prediction. Though multiphase modelling is technically possible, it cannot be confidently deployed for field scale problems due to lack of validation and excessive requirement for computational resources. When simulating multiphase flow through a long horizontal pipe, it is important to specify appropriate boundary conditions for the gas and liquid phases at the inlet which can correctly define the slug length and velocity. This paper presents a translational periodic Computational Fluid Dynamics (CFD) model which can effectively capture slug flow in horizontal pipes as the slug unit cell can be approximated as periodic in the axial direction. The simulation of the slug flow was performed in a pipe section, with periodic boundary conditions under imposed pressure gradient and fixed overall liquid hold-up. Starting from smooth stratified flow, the slug flow pattern is simulated and validated in terms of slug speed and superficial velocities for gas and liquid phases.
Furthermore, sensitivity studies were performed to understand the effect of mesh resolution, turbulence model, multiphase model, and time step size on CFD predictions in translationally periodic horizontal straight pipes. Experimental datasets of Manolis (1995) on high pressure gasliquid slug flow for hydrodynamic slugging in a horizontal pipe were used to validate multiphase CFD modelling. Subsequently an efficient algorithm was developed to couple results from periodic domain model of straight pipe to a more complex pipe configuration with one (or more) 90° bends. This algorithm was successfully demonstrated on TNO FIV JIP dataset (Belfroid et Al., 2016) for prediction of multiphase flow behavior and fluid forces in horizontal pipe with bend.
A Hindcast Model for Evaluation of Iceberg Management Operations
Authors: Fuglem Mark , Stuckey Paul , Turnbull Ian , Thijssen Jan , Huang Yujian 
Published: October 2021

Abstract
When planning oil and gas exploration and production operations off the east coast of Canada, the potential for iceberg impacts must be considered. Environmental conditions in this region can be very harsh, and iceberg trajectories are notably unpredictable. When an iceberg has the potential to impact a Floating Production, Storage, and Offloading (FPSO) platform, ice management through towing will be attempted; and if this fails, the production system will be shut down, line flushed, the mooring and riser systems disconnected, and the platform moved off site.
If trajectory forecasting were highly accurate, only icebergs passing very close to the platform would require ice management and possible shutdown of the platform. Given natural variations in wind, currents, and waves, and challenges measuring and forecasting these parameters, there is considerable forecast uncertainty. This results in added expenses for extra ice management and unnecessary shutdowns.
Improvements in trajectory forecasting accuracy, characterization of forecast uncertainty, and methods to account for these uncertainties in operations would all be beneficial. This paper outlines an approach for simulating large numbers of iceberg trajectories in varied and realistic environmental conditions from hindcast met-ocean data in conjunction with a forecasting uncertainty model derived from forecast validation studies. A model, named BergCast, was developed so that proposed strategies for improving ice management operations can be evaluated, and the value of reducing forecasting uncertainty quantified.
Development of Iceberg Profiling Technology
Authors: Bruce Jonathon , Yulmetov Renat , King Tony , Ralph Freeman , Younan Adel 
Published: October 2021

Abstract
Iceberg management on the Grand Banks of Newfoundland, Canada is currently carried out without knowledge of the underwater shape of the iceberg. An iceberg profiling system is being developed to integrate the rapid generation of 3D iceberg shape data with a collection of tools that utilize the data to provide recommendations, intended to improve iceberg management effectiveness. The intent is for the system to be operated by vessel crew with minimal training.
The system utilizes a LiDAR and a pole mounted multibeam sonar to profile the iceberg sail and keel, respectively. A vessel equipped with the profiling system circles an iceberg twice to collect a profile, a process that on average requires approximately 15–30 minutes. The data is collected in the form of a point cloud, which must be de-noised and corrected for both drift and rotation of the iceberg. Tools have been developed to assess the stability of the iceberg, and to consider the shape of the iceberg relative to towing net dimensions, to provide guidance to the operator regarding the recommended towing direction to avoid iceberg rolling or net slippage events. Other applications of the profile data include an impact loads analysis tool that determines the distribution of potential iceberg loads in the event of a collision with a given platform, and an operational iceberg drift model that uses the iceberg shape to improve iceberg drift forecasts.
Large-scale field programs were carried out in both 2018 and 2019 as part of the development process for the system. Data collected has shown that iceberg characteristics have changed significantly when compared to iceberg profile data collected in the 1980s. For a given iceberg waterline length, the more recent data shows significantly reduced drafts. The 1980s iceberg dataset currently dominates the data used as the basis for assessing iceberg loads on surface facilities and iceberg risk to subsea assets. Reduced iceberg drafts will result in reduced risk to subsea facilities and pipelines.
These results and observations demonstrate the usefulness of the iceberg profiling system as an environmental monitoring tool, and the data collected has design and operational applications. The development and capabilities of the system are presented, as well as the comparison of the 1980’s and newer iceberg datasets and implications for iceberg risk to facilities on the Grand Banks and surrounding regions.
The Evolved Motions of a Marine Riser or Pipeline
Authors: Zueck Robert F. 
Published: October 2021

Abstract
Analytical, experimental and computational models have historically been heavily simplified, linearized, and otherwise reduced. This paper shows how such model reductions eliminate the fundamental geometric changes that determine real behavior in cables, strings, moorings, guys, pipelines, riser, plates, skins, subsea hulls, and other such slender and thin structures. The paper details each physical quantity that we must add back into our overly reduced models to improve the basic nature, evolution, and accuracy of the resulting motions and vibrations.
For example, even slight changes in local rotation anywhere along a cable can create large nonlinear changes in the dynamic nature of its behavior. The evolved complexity of the resulting global motions and vibrations in space and time often defy what we normally expect from such a simple structure.
Although this paper focuses on the modeling of deep-water moorings and risers of an ocean platform, the same geometric effect is fundamental to most science and engineering models. Understanding how small changes in geometry can nonlinearly affect any structured behavior will help demystify much of the poorly-understood motions and vibrations in a large diversity of applications, including induced vibrations, sound, structural acoustics, aero-elasticity, sound, light and atomic radiation.
FPSO Mooring Line Integrity Supervising System Based on Motion Data and Natural Frequency Estimation
Authors: Costa José Lucas De Melo , Queiroz Filho Asdrubal N. , Santos Ismael H. F. , Barreira Rodrigo Augusto , Costa Anna Helena Reali , Gomi Edson Satoshi , Tannuri Eduardo Aoun 
Published: October 2021

Abstract
Offshore production facilities play a central role in the oil industry given the growing demand for energy resources. The mooring system of these floating structures is a critical component for safety maintenance. The timely identification of mooring lines failures can prevent environmental pollution, property losses and further system failures. In this paper we propose a system to detect and classify failures of the mooring lines based on the natural period in the longitudinal axis and in the lateral axis of the long drift oscillatory motion of the platform. The proposal starts from the hypothesis that when a line break occurs, the natural period of oscillation of the platform is increased, and this difference may indicate the malfunction of the mooring system. The proof of concept developed for the proposed system demonstrates the potential of using the natural period to detect failures in mooring lines for floating vessels, validating the initial hypothesis that the difference in a natural period appears when a line breaks and that this difference may detect line break.
Fatigue Life Extension Procedure for Subsea Wells Based on Pressure Testing
Authors: Fjeldstad Arne , Hørte Torfinn , Sigurdsson Gudfinnur , Wormsen Anders , Berg Espen , Macdonald Kenneth Alasdair , Reinås Lorents 
Published: October 2021

Abstract
This article presents a fatigue life extension procedure for subsea wells based on fracture mechanics. It makes use of the outcome of an internal pressure test to determine a safe period for drilling and completion. The pressure test is used as a load test and can only reveal deep fatigue cracks. The safe operational period is estimated as the number of cycles required to grow a fatigue crack from the largest fatigue crack that remains stable after the pressure test until it becomes unstable due to an accidental load. The procedure takes into account the probability of the presence of the fatigue crack that can be revealed by the pressure test. This is used to determine design fatigue factors for the procedure. The design fatigue factor is formulated in terms of the (S-N based) accumulated fatigue damage for historical operations. The procedure is illustrated with two case examples (fatigue hot spots) for illustrating the procedure in more detail: wellhead extension girth weld and wellhead profile. Conditions for use are given at the end of the article.
Flow of Yield Power Law Fluids in Horizontal Pipes-Flow Field Characterization Using Particle Image Velocimetry Technique
Authors: Sun Yanxin (Sussi) , Abou-Kassem Abdulla , Bizhani Majid , Kuru Ergun 
Published: October 2021

Abstract
Yield Power Law (YPL) rheological model is commonly used to describe the pipe and annular flow of drilling fluids. However, the hydrodynamic behaviour of fluids with yield stress are difficult to predict because they exhibit an inherent plug (solid like) region where the velocity gradient is zero. Moreover, it is not easy to identify the transition between this solid like and liquid regions.
Theoretical studies have been conducted in the past to describe YPL fluid flow in pipes and annuli. As a result, several models have been proposed for determining flow field characteristics (e.g. velocity profile, plug width, etc.) and frictional pressure losses. However, most of these models have been validated by limited experimental and/or field data. Similar future modeling studies may benefit from more data collected under controlled experimental conditions. Therefore, we have conducted an experimental study to investigate the hydrodynamic behaviour of yield stress fluids under laminar pipe flow conditions and the results are presented in this paper.
Water-based Yield Power Law fluids were prepared by using Carbopol® 940, a synthetic high-molecular-weight polyacrylic acid-based cross-linked polymer. Fluids with yield stresses varying from 0.75 Pa (1.56 lb/100 ft2) to 4.37 Pa (9.13 lb/100 ft2) were obtained by using Carbopol concentrations changing from 0.060% w/w to 0.073% w/w. A 9m long horizontal pipeline with, 95 mm diameter (ID) was used for the experiments. Reynolds number range varying from 97 to 1268 confirmed that all flow field characteristics measurements of YPL fluids were conducted under laminar flow regimes.
Experimental study provided detailed information about pipe flow characteristics of yield stress fluids, including full annular velocity profile, near wall velocity profile, wall slip velocity and the plug region thickness.
The study was concluded by comparing experimental results (i.e. full velocity profile, frictional pressure loss, and plug width) to predictions of models presented in the literature.
Practical implications of the results have also been discussed by considering the hydraulic design of some practical field operations such as hole cleaning.
Susceptibility to Preferential Corrosion of Pipeline Welded Joints in Condensed and Dragged Water Droplet - Part 1
Authors: Zumpano Petrônio , Cardoso Juliana L. , Panossian Zehbour , Baptista Ilson P. , Miranda Helio , Franco Marilia F. 
Published: October 2021

Abstract
Preferential weld corrosion (PWC) is due to the formation of galvanic cells between the weld metal (WM), the parent metal (PM) and the heat affected zone (HAZ). This work has studied PWC susceptibility in longitudinal and circumferential welded joints of submarine systems and the applicability of corrosion inhibitors to mitigate the corrosive process. DNVGL SAW 450, DNVGL SMLS 450 and low alloy forged, with different nickel, copper and silicon content were tested. Several factors influence PWC susceptibility in welded structures and those selected to be studied were weld joint geometry, PM fabrication process, welding process and welding consumable chemical content. For each welding processes, welded coupons were made with similar heat input. Pipe SAW seam welds of two different plate suppliers and different nickel and copper content were tested. Tests in circumferential weld joints were predicted for 79 different combination of chemical composition: PM chemical composition and manufacturing process; welding processes; chemical composition of welding consumables. Selected welding processes are the most used by offshore industry (SAW, mechanized GMAW and manual GTAW). The root configuration of respective welding procedure specifications produce a desired variation in width geometry. The corrosion tests started with the longitudinal joints and will be further reproduced for circumferential joints. A test procedure has been developed for corrosion evaluation through immersion test, galvanic current measurement (GCM) through zero resistance ammeter (ZRA) and localized electrochemical test through SVET. Two test solutions were considered, simulating condensed and dragged water droplets in order to verify the susceptibility or occurrence of the preferential welding corrosion in the welded joints. The results for longitudinal joints indicated a greater susceptibility to PWC in dragged water than in condensed water droplets and a greater susceptibility of joints with greater anodic potential due to a higher nickel and copper content in the parent metal. A correlation between the corrosion rates obtained in both medium and the moisture contents of gas pipelines will be performed to determine the need for the addition of corrosion inhibitors and to establish the minimum required dosage. A future work will involve circumferential joints and the evaluation of the optimal dosage of corrosion inhibitors.