bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Expected Loss by Storm Surges Along Tokyo Bay Coast
Authors: Hisamatsu Rikito , Kim Sooyoul , Tabeta Shigeru 
Published: November 2019

Abstract
In Japan, the fundamental disaster management plan was modified after a heavy rainfall event in 2015. According to the updated plan, the transfer of flood disaster risk to non-life insurance is promoted by the Japanese government. Thus, the importance of flood risk modeling for the insurance industry has increased.
Winds are expected to become even stronger, resulting in higher storm surges, when the central pressure of the typhoon is intensified. Furthermore, it is possible for an insurance system to experience peak risk when such damage occurs simultaneously. Hence, refining the assessment method of storm surge risk is very important.
An insurance company to which storm surge risk is transferred needs to assess not only the infrequent risks, for managing the risk of the company, but also the expected value of the estimated loss, for evaluating the insurance premium. However, only a few studies have assessed storm surges by stochastic approaches.
In this study, storm surge losses along the coast of Tokyo Bay are predicted using the output of a stochastic typhoon model for 10,000 years. Storm surge losses due to 600 typhoons potentially causing storm surge damage for 10,000 years are calculated. Exceedance probability curves (EP curves) of estimated storm surge loss for each asset are created. Expected loss and the loss of representative return periods are evaluated based on these EP curves. We successfully determined the expected loss with a small calculation load.
Evaluation of a Practical Approach for Numerical Propulsion Tests
Authors: Giannoulis Andreas , Halse Karl H. 
Published: November 2019

Abstract
Prediction of resistance and propulsion characteristics for a ship is among the most important steps in a ship design process. Traditionally, model tests are used for these predictions and the results are extrapolated to the full-scale ship. Model test techniques can provide reasonably accurate results, but the cost and time they require — and the unavoidable scaling issues — have lead Naval Architects to look for other alternatives.
With the increasing computer power and the increasing experience with numerical simulation of fluid flow, Computational Fluid Dynamics (CFD) have become an appealing alternative to model tests. Numerical computations will always be a trade-off between computational efforts and numerical accuracy. Typically, increased accuracy requirements will cause the mesh to be very fine, and hence the computational time will increase.
At a Workshop on numerical simulation of full-scale ships in Southampton in November 2016, a practical approach for predicting the propulsion characteristics of a full-scale ship was introduced by participants from Becker Marine Systems. The pragmatic CFD approach reduced the computational efforts without scarifying the level of accuracy! In the present work, the alternative practical CFD approach is evaluated in a model scale case to study its benefits and possible short-comings compared to conventional CFD simulations of the self-propulsion case.
Force Measurements and Stationarity Analysis on the Flow Around a Single Square Column With Rounded Edges
Authors: Gambarine Dennis , Koop Arjen , Assi Gustavo , Rampazzo Fabiano , Gonçalves Rodolfo T. 
Published: November 2019

Abstract
Studies about the flow around single column are the preliminary way to understand the behaviour of multi-column systems, e.g. semi-submersible platforms and floating offshore wind turbines. The presence of a rounded edge in a square column can include advantages in the constructive phases, on the other hand, can include difficulty in understanding the hydrodynamic behaviour. With this aim this paper presents a 2dof force measurement for a fixed single square column with and without rounded edges. The columns tested have the aspect ratio (H/L) equal to 1.5 representing the typical column height for multi-column platforms. The aim is to investigate the forces between a single square column with rounded edges and sharp edges in different flow incidence. For both edges a total of seven different current incidence angles were performed; 0, 7.5, 15, 22.5, 30, 37.5 and 45. Reynolds number used for the experiment is equal to 40,000. Additional tests were performed to evaluate a quantitative analysis of the uncertainties due to the repeatability and time length of the experiments. This procedure is necessary for the VV studies of CFD codes, and due to this, the database can be utilized for benchmarking.
Full Scale Thermal Testing of a New Flowline Intervention System
Authors: Harchambois Stéphanie , Le Toux Vincent , Guindeuil Geoffrey , Vivet Romain , Pasquet François-Xavier , Tosi Guillaume , Palermo Thierry , T'Joen Christophe , Herrera Gilbert 
Published: November 2019

Abstract
The Electrically Trace Heated Blanket (ETH-Blanket) is a new offshore intervention/remediation system currently in development by TechnipFMC for the efficient remediation of plugs due to hydrates or wax in subsea production and injection flowlines. The ETH-Blanket consists of a network of heating cables placed underneath an insulation layer which is laid onto the seabed above the plugged flowline. By applying electrical power to the cables, heat is generated by Joule effect which warms up the flowline content until hydrate dissociation or wax plug remediation through softening or complete melting.
As part of a Joint Industry Project (JIP) between TechnipFMC, Shell and Total, full-scale thermal testing of an ETH-Blanket prototype was carried out in Artelia facilities (in Grenoble, France). This testing was performed to verify the capability of the ETH-Blanket system to increase the temperature of the fluid inside a pipe sample above a target temperature (hydrate dissociation temperature or wax disappearance temperature) for various conditions. The impact of lateral misalignment of the ETH-blanket on the pipe and of the pipe burial depth were studied. Moreover, the tests were carried out on two pipe samples, with different designs and insulation properties. In parallel, CFD models of the test set-up were built to replicate the thermal behaviour of the ETH-Blanket. The combination of these models with the measured heating efficiency of the prototype allowed characterising the performances of the system in real subsea conditions.
This paper presents the description of the full scale thermal testing conditions. Results of the different tests are detailed and the impact of the different parameters on the ETH-Blanket thermal performances are assessed, focusing on natural convection effects, thermal losses and the overall data gathering process.
Wave-Powered AUV Recharging: A Feasibility Study
Authors: Driscol Blake P. , Gish Andrew , Coe Ryan G. 
Published: November 2019

Abstract
The aim of this study is to determine whether multiple U.S. Navy autonomous underwater vehicles (AUVs) could be supported using a small, heaving wave energy converter (WEC). The U.S. Navy operates numerous AUVs that need to be charged periodically onshore or onboard a support ship. Ocean waves provide a vast source of energy that can be converted into electricity using a wave energy converter and stored using a conventional battery. The Navy would benefit from the development of a wave energy converter that could store electrical power and autonomously charge its AUVs offshore. A feasibility analysis is required to ensure that the WEC could support the energy needs of multiple AUVs, remain covert, and offer a strategic military advantage. This paper investigates the Navy’s power demands for AUVs and decides whether or not these demands could be met utilizing various measures of WEC efficiency. Wave data from a potential geographic region is analyzed to determine optimal locations for the converter in order to meet the Navy’s power demands and mission set.
Study on Residual Strength of Egg-Shaped Pressure Shell With Local Damage
Authors: Yuan Siming , Gao He 
Published: November 2019

Abstract
The eggshell is a multifocal, rotary thin-walled structure that satisfies the positive Gaussian curve. The eggshell meets the dome principle and requires no additional rib support to achieve sufficient strength and stability with minimal material. Some scholars have applied this bionic prototype to the pressure-resistant shell, which proves that it has good comprehensive performance. However, there is less in-depth discussion of the buckling characteristics of this new pressure-resistant shell yet. In this paper, the dangerous situation of collision, reefing and other accidents during the use of deep submersibles is considered, the residual strength of the shell with partial damage is studied, which is of practical engineering significance. Firstly, the ABUQUS finite element software is used to calculate the buckling of the egg-shaped pressure shell with local deformation, and the influence of local deformation on the buckling mode and ultimate bearing capacity of the pressure shell is analyzed. Secondly, by designing the pressure-resistant shells with different concave amplitudes and recessed positions, the influence of the pressure-resistant shell on the stability of the pressure-resistant shell is analyzed. Finally, according to the calculation results, the sensitivity law of different concave positions to the concave amplitude is summarized, and the beneficial engineering opinions are given.
Three-Dimensional Numerical Simulations of Severe Gas-Liquid Slugging Flows in S-Shaped Riser
Authors: Moon Youn-Wook , Srinil Narakorn , Park Jong-Chun 
Published: November 2019

Abstract
S-shaped riser may be used for connecting a subsea well and floating platform for the multiphase oil-gas flow transportation. A buoyancy module is installed in the longitudinal direction of the riser section enabling a hog and sag bend arrangement. This design offers a solution to decouple motion from the boundaries and lower the riser stresses. There is an increasing tendency to implement S-shaped risers for offshore platforms operating in deep waters or harsh environments. However, a generic S shape may cause a terrain-induced, severe slugging under certain practical operational/geometrical conditions and flow rates. This phenomenon leads to unstable and intermittent slug flows creating fluctuations of pressure, fluid fraction and velocity components. In this paper, the flow pattern characteristics and formation process of a severe slugging in an S-shaped rigid riser transporting the liquid-gas flows are studied using 3-D computational fluid dynamics simulations based on a finite volume method. Numerical results are validated by comparing with experimental results in the literature. Severe slugging behaviors are presented and discussed.
Component-Based Modeling and Simulation of Nonlinear Drill-String Dynamics
Authors: Tengesdal Njål , Holden Christian , Pedersen Eilif 
Published: November 2019

Abstract
In this paper, we present a dynamic model for a generic drill-string. The model is developed with the intention for component-based simulation with coupling to external subsystems. The performance of the drill-string is vital in terms of efficient wellbore excavation for increased hydrocarbon extraction. Drill-string vibrations limit the performance of rotary drilling; the phenomenon is well-known and still a subject of interest in academia and in industry. In this work, we have developed a nonlinear flexible drill-string model based on Lagrangian dynamics, to simulate the performance during vibrations. The model incorporates dynamics governed by lateral bending, longitudinal motion and torsional deformation. The elastic property of the string is modeled with mode shape functions representing the elastic deformation, with a finite set of modal coordinates. By developing a bond graph model from the equations of motion, we can ensure correct causality of the model towards interacting subsystems. The model is analyzed through extensive simulations in case studies, comparing the qualitative behavior of the model with state-of-the art models. The flexible drill-string model presented in this paper will aid in developing simulation case studies and parameter identification for offshore drilling operations.
Improved Pipelay Equipment Settings Methodology for Rigid Pipes
Authors: Marmonier Geoffrey , Harrop Andrew , Lacan Ludovic 
Published: November 2019

Abstract
Rigid pipelay vessels use two types of equipment to hold the pipe under tension while it is being deployed on the seabed: tensioners and hang-off clamps (HOC). Tensioners are used to maintain tension while paying out the pipe behind the vessel, while the HOC holds the pipe statically during welding operations. For both pieces of equipment, the tension is held through frictional pads in contact with the pipe.
With the necessity to reach greater water depths leading to an overall increase of pipeline weights and stiffness (and therefore top tension), the installation of rigid pipelines has become more challenging. In other cases, such as pipe-in-pipe (PiP), carrier pipe wall thicknesses are often optimised as much as possible while lower grade materials are selected to reduce costs, making it more difficult to provide pipelay equipment settings that can satisfy both grip and pipe local integrity requirements. Simple hand calculations and basic equipment modelling are not sufficient to provide safe equipment settings and optimised allowable sea states. The new DNVGL-ST-N001 [1] (Marine Operations and Marine Warranty) also increases scrutiny on pipelay equipment and pipe interaction, making it imperative to develop more in-depth methodologies for settings calculation.
This paper gives an overview of a robust methodology for pipelay equipment settings and demonstrates through practical examples how it improves safety while optimising operations, therefore enabling more efficient pipelay operations and reducing waiting on weather.
Architectures and Algorithms for a Smart Drilling Robot
Authors: Geekiyanage Suranga C. H. , Løken Erik A. , Sui Dan , Wiktorski Tomasz 
Published: November 2019

Abstract
Robotic drilling is likely to become a key feature of the next generations of drilling rigs and novel drilling technical solutions. We have been developing a drilling robot on a laboratory scale to run different drilling scenarios and achieve high-level performances with less or even no human intervention. In this paper, we introduce its mechanical systems, perception capabilities, data management, decision-making algorithms, and digital architecture. Results illustrate its autonomous operations, incident management capabilities, learning outcomes, improvement potential, and challenges. Lab testing and evaluation is an essential part of implementing, promoting and accelerating robotic applications of drilling automation. Our drilling robot is a useful, safe and cost-effective solution for testing, integrating and improving hardware, software, data, and digital/robotic products in a laboratory scale, before expensive full-scale testing and integration.
Feature Selection for Kick Detection With Machine Learning Using Laboratory Data
Authors: Geekiyanage Suranga C. H. , Ambrus Adrian , Sui Dan 
Published: November 2019

Abstract
Conventional kick detection methods mainly include monitoring pit gains, surface flow data (flow in and flow out), surface and down-hole pressure variations, and outputs from physics-based models. Kick detection times depend on a driller’s individual ability to interpret these drilling measurements, symptoms and model predictions. Furthermore, testing a novel data-driven solution in a full-scale operation may induce non-productive time, safety risks and crew fatigue adding to false alarms that inevitably occur during testing. Therefore, the development of better, faster and less human intervention-dependent kick detection on a laboratory scale system is a valuable step before full-scale testing.
We have generated a dataset containing seven typical drilling measurements and a sequence of gas kicks from experiments conducted in the laboratory scale. First, we employ data analysis tools following data pre-processing steps, data scaling, outlier detection, and natural feature selection. Next, we consider additional “engineered features” and apply different feature combinations to logistic regression with an ensemble method (boosting) for developing kick detection algorithms.
In our data analysis, ‘Delta flow’ (difference between flow in and flow out of the well) and ‘Rate of change of delta flow’ designed features, combined with logistic regression and boosting, give promising results in detecting kicks. Finally, we propose an intelligent algorithm and alarm architecture for a complete kick alarm system, which draws from both data analysis and machine learning models developed in this work.
Water Wave Scattering by Two Circular-Arc-Shaped Thin Plates With Non-Uniform Permeability
Authors: Gayen R. , Gupta Sourav 
Published: November 2019

Abstract
The interaction of small amplitude water waves with a pair of circular-arc-shaped thin porous plates is studied under the assumption of linear theory. The plates are submerged at different depths in deep water and the permeability of the plates varies along the circumference of the plates. Applying Green’s integral theorem to the fundamental potential function and the scattered potential function and using the condition on the porous plates, the problem is reduced to that of solving a set of coupled integral equations for the potential difference functions across the plates. Two kernels of these integral equations are hypersingular and the other two kernels are regular. An expansion-cum-collocation method involving Chebyshev polynomials is employed to obtain the approximate solution of the integral equations. The numerical estimates for the reflection and the transmission coefficients are computed utilizing the approximate solution of the aforesaid integral equations. The numerical results for the reflection and the transmission coefficients are depicted graphically for several values of various parameters. Known results for dual symmetric circular-arc-shaped porous plates are recovered as special case.
Design of Buried Pipelines in Soft Clay: A Case Study
Authors: Gallegillo Martin , Cerulli Michele , Haghighi Ali , Kennedy Justin 
Published: November 2019

Abstract
High pressure high temperature offshore pipelines are generally buried for protection. For buried pipelines, upheaval buckling can be triggered in the presence of vertical imperfections when the pipeline compressive state is increased. One of the main uncertainties in the design calculation is the soil resistance to upward and downward movement and the displacement at which the peak resistance is mobilised. For clays the soil response will usually be undrained, certainly for most loading events, however it may also be necessary to consider the drained response (particularly if there is any long term applied uplift). In addition, local flow-round failure mechanism may occur, generally for deeply buried pipelines. If local failure dominates the design, it may not be possible to bury the pipeline. This could have significant cost implications.
An experimental programme was carried out to determine the uplift resistance of buried pipelines in soft clay soils. The results of scale model testing and computational analysis (finite element limit analysis) showed that the local behaviour was not applicable. The implications of these results are illustrated in a case study upheaval buckling (UHB) analysis. The overall result was a significant saving on rockdump quantities. The implications for the case study are presented in this paper alongside a description of other backfill requirements and practical considerations for a UHB design.
Numerical Investigation of Ductile Crack Growth Behavior at Different Locations of Weld Joint for X80 Pipeline Steel
Authors: Qiang Bin , Wang Xin 
Published: November 2019

Abstract
The finite element method (FEM) based on the Gurson–Tvergaard–Needleman (GTN) model was used to investigate the ductile crack growth behavior at different weld joint locations in X80 pipeline steel. The X80 weld joints are inhomogeneous and can be divided into five different zones. By fitting the results of uniaxial tension and single-edge notched bending tests, the GTN model parameters were determined using FEM in consideration of the inhomogeneity of the weld joint. The calibrated GTN model was then used to analyze the fracture toughness in single-edge notched tension tests. The results show that the different weld joint zones produce different mechanical properties and crack growth resistance curves. To accurately assess the integrity of X80 weld joints, the calibrated GTN model is a reasonable method for obtaining fracture toughness data and resistance curves for different joint locations under different loading conditions.
Vessel Interface Considerations for Ultra Deepwater Intervention Risers
Authors: Vaidya Rohit , Sonawane Mahesh , Toleman Benjamin , Whiteley Elaine , Rourke Jonathan 
Published: November 2019

Abstract
For ultra-deepwater subsea wells, a riser system is required to conduct completion, intervention/workover and end of life activities. For ultra-deepwater riser systems with high temperature and pressure requirements, the intervention riser system often requires vessel interface optimization to achieve acceptable design response. The upper riser can be configured in several different ways, each with its own benefit from a safety, risk and performance perspective. This paper compares the riser response for various vessel interfaces for ultra-deepwater applications.
As discussed above, intervention riser structural response is sensitive to the riser configuration at the vessel interface. For a typical intervention riser, due to ultra-deepwater and high tension requirements, the functional tension load may utilize up to 40% of yield strength thus decreasing the capacity available to accommodate bending and pressure loads. Vessel operators have options to modify the system configuration to improve the strength and fatigue response of the riser. The different vessel interface options include the tension lift frame (TLF) to vessel interface, the top tension application method and the use or otherwise of a surface tree dolly. Upper riser assembly (URA) loads may be optimized by use of rotary wear bushings, a cased wear joint assembly or flexjoints as a part of the stack-up.
The various riser-vessel interface options are evaluated and compared in this paper. This paper highlights the riser design challenges for ultra-deepwater applications.
Design and Construction of a 1/15th Scale Wave Tank Model of the Azura Commercial Wave Energy Converter
Authors: Ling Bradley A. , Lettenmaier Terry , Fowler Matthew , Cameron Matthew , Viselli Anthony M. 
Published: November 2019

Abstract
The design of a 1/15th geometrically scaled wave tank model of the Azura™ commercial-scale wave energy device is presented. The objectives of the wave tank tests, conducted at the University of Maine Harlod Alfond Wind/Wave Ocean Engineering Lab (W2), included verification of the Azura’s energy capture in irregular waves, evaluation of performance in survival wave conditions, and testing of two advanced control algorithms. Due to the difficulty in properly Froude Scaling a hydraulic system, the model used a direct-drive rotary motor/generator power takeoff (PTO), with the dynamics of the hydraulic PTO included via a hardware-in-the-loop simulation. This PTO implementation led to additional design requirements being imposed on the model drivetrain. In addition to the model PTO design, the instrumentation design, structural design, and test plans are presented. The resulting model and PTO achieved a high level of controllability, and accurately emulated the dynamics of the hydraulic PTO of the full-scale Azura prototype.