bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear Evolution of a Narrow-Banded Surface Gravity Wavepacket Over an Infinite Step
Authors: Li Yan , Adcock Thomas A. A. , van den Bremer Ton S. 
Published: November 2019

Abstract
This paper focuses on the classical and fundamental problem of waves propagating over an infinite step in finite water depth. Specifically, this paper aims to extend classical narrow-banded wave theory for constant water depth which uses a multiple-scales expansion to the case of an abrupt change in the water depth, known as an infinite step. This paper derives the linear evolution equations and is the first step towards the calculation of second-order and higher-order effects for wavepackets travelling over a step using commonly employed envelope-type evolution equations, in particular the bound sub- and super-harmonics at second order.
Vortex Induced Vibration of a Steel Catenary Riser Under Out-of-Plane Current: An Experimental Study
Authors: Xu Yuwang , Wang Jungao , Ren Haojie , Zhang Mengmeng , Fu Shixiao 
Published: November 2019

Abstract
To investigate the VIV characteristics and to further develop the corresponding numerical predictions of a steel catenary riser under out-of-plane current, a large-scale model of a steel catenary riser was towing in an ocean basin at various speeds and directions. Fiber Bragg grating strain sensors are instrumented on the riser model to measure both in-plane and out-of-plane responses. The vortex-induced vibration responses of the steel catenary riser under out-of-plane current, i.e., the oscillating amplitude, the response frequency, and the traveling wave phenomenon, are compared with those under the in-plane current.
A Probabilistic Approach to Tropical Cyclone Modelling
Authors: Grey Stephen , Liu Ye 
Published: November 2019

Abstract
Tropical cyclones are highly variable and, in many areas of the world, are the main cause of extreme wind and associated waves, surge and current conditions. At a given location, cyclones that cause a significant impact are relatively rare but severe events, which means that the number of historical events for which data are available is often quite small. In addition, the effects, particularly surge, can be relatively localized and affected by the local bathymetry and topography. This causes considerable difficulty in making quantitative predictions of extreme events for design of offshore or coastal structures in areas affected by tropical cyclones.
A new probabilistic method has been developed to increase the sample of tropical cyclones by producing 10,000 years of synthetic cyclone tracks with a range of paths, intensities and sizes based on Hall and Jewson [1] and Casson and Coles [2]. From this set of synthetic tracks, those tropical cyclones most likely to affect the site of interest are modelled using time-varying wind fields based on the Holland model [3] with surge, current and waves then modelled using the hydrodynamic model TELEMAC-2D coupled to the SWAN wave model. As it is impractical to model 10,000 years of tropical cyclones, a Gaussian process emulator is employed to relate the resultant conditions to parameters defining the cyclones, such as track position, heading, intensity and radius to maximum wind.
The result is a synthesized 10,000 years of cyclone events from which design conditions for a range of return periods can be predicted with a greater degree of certainty than by extrapolating from historical events.
Quantification of Predicted Wave Forces From Distant Elevation Measurements
Authors: Hallowell Spencer T. , Arwade Sanjay R. , Johlas Hannah , Lomonaco Pedro , Myers Andrew 
Published: November 2019

Abstract
The vast spatial scale of offshore structures causes wave loading to be correlated amongst nearby structural members. Certain engineering activities including health monitoring, maintenance, and preliminary design of offshore structures requires the prediction of wave forces on said structural members. The high cost and low availability of environmental wave measurements requires the reconstruction of wave kinematics and force profiles to accurately capture the forcing history on offshore structures. A method for predicting wave forces on a cylinder from nearby wave elevation measurements is proposed. The formulation utilizes the Fast Fourier Transform to calculate wave kinematics propagation in the frequency domain and applies the kinematics to the Morison equation for calculation of cylinder forces. The prediction equations are applied to three types of waves: regular periodic waves, random irregular waves, and solitary breaking waves, and the error in both elevation prediction and force prediction when compared to measured values is calculated. The force prediction equations were shown to perform best for small wave heights, with errors as low as 5% in the force predictions for small regular and irregular waves. The error in force prediction increases nonlinearly with the increase in wave height due to the deficiencies of the linear dispersion relationship used in the formulation.
Nonlinear Airy Wave Pulses on the Sea Surface
Authors: Shugan Igor , Kuznetsov Sergei , Saprykina Yana , Chen Yang-Yih 
Published: November 2019

Abstract
The possibility of self-acceleration of the water-wave pulse with a permanent envelope in the form of the nonlinear Airy function during its long propagation in deep water is experimentally and theoretically analyzed. This wave packet has amazing properties — accelerates without any external force, and preserves shape in a dispersive medium. The inverted Airy envelope wave function can propagate at velocity that is faster than the group velocity. We experimentally study the behavior of Airy water-wave pulses in a super-tank and long scaled propagation, to investigate its main properties, nonlinear effects and stability. Theoretical modeling analysis is based on the nonlinear Schrodinger equation. We investigate the scope of applicability, feasibility and stability conditions of nonlinear Airy wave trains in the deep water conditions; defining regimes of self-acceleration of the main pulse, immutability shape of Airy envelope; assessing the impact of nonlinearity and dissipation on the propagation of Airy waves. We analyzed the influence of the initial pulse characteristics on self-acceleration of wave packet and the stability of the envelope form. The anticipated results allow extending the physical understanding of the evolution of nonlinear dispersive waves in a wide range of initial conditions and at different spatial and temporal scales, from both theoretical and experimental points of view. Steep waves start to become an unstable, we observe spectrum widening and downshifting. Wave propagation is accompained by the intensive wave breaking and the generation of water-wave solitons.
Parameter Calibration for Continuum Damage Mechanics Models to Simulate Ductile Fracture of High Strength Pipeline Steels
Authors: Van den Abeele Filip 
Published: November 2019

Abstract
The ability to arrest a running crack is one of the key features in the safe design of pipeline systems. In the industry design codes, the crack arrest properties of a pipeline should meet two requirements: crack propagation has to occur in a ductile fashion, and enough energy should be dissipated during propagation. While the first criterion is assessed by the Battelle Drop Weight Tear Test (BDWTT) at low temperatures, the latter requirement is converted into a lower bound for the impact energy absorbed during a Charpy V-notch (CVN) impact test. However, the introduction of high strength pipelines steels (X70 and beyond) has revealed that the commonly used relations based on BDWTT and CVN no longer hold. For such scenarios, Continuum Damage Mechanics (CDM) models provide promising potential to obtain a more profound understanding of the mechanisms that govern ductile crack propagation in high strength pipeline steels.
In recent years, different types of CDM models have been used to simulate ductile fracture of pipeline steels. This paper focuses on two of these models, i.e. the Gurson-Tvergaard-Needleman (GTN) model and the Modified Bai-Wierzbicki (MBW) model. The GTN model is based on the computation of void growth according to Rice and Tracey, and account for the local softening of the material due to void nucleation, growth and subsequent coalescence. The MBW model is a fully coupled damage model, where the yield surface depends on both the stress triaxiality and the Lode angle. Although both models can predict ductile fracture propagation, their widespread application in pipeline design is hampered by the large number of input parameters to be calibrated. The GTN model requires 10 input parameters, i.e. 3 Tvergaard damage parameters, 4 porosity parameters and 3 parameters to describe void nucleation.
Whereas the Modified Mohr-Coulomb model originally proposed by Bai and Wierzbicki uses merely 2 parameters, the extended MBW model requires no less than 18 parameters to be calibrated: 11 plasticity parameters (5 stress + 3 strain rate + 3 temperature) and 7 damage parameters (4 initiation + 1 propagation + 2 failure).
In this paper, different numerical/experimental strategies to calibrate these parameter sets are reviewed and compared. Sensitivity analyses are performed to assess the influence of the different input parameters on the model predictions. For both GTN and MBW models, the robustness and uniqueness of the calibrated parameter sets is investigated. Recommendations on optimum parameter values are derived, with special emphasis on high strength pipeline steels.
Estimation of Roll Damping Coefficients Based on Model Tests Responses of a FPSO in Waves
Authors: Rodríguez Claudio A. , Esperança Paulo T. T. , Oliveira Mauro C. 
Published: November 2019

Abstract
Roll damping estimation is of great concern for the prediction of motions in waves of ship and offshore platforms, especially when viscous effects are relevant. Although this problem dates back to the times of William Froude, it has regained much attention in the context of the development of the second-generation intact stability criteria of ships, especially because there are still not accurate and efficient tools for roll damping prediction. For offshore applications, a common approach for roll damping estimation is to perform roll decay tests with scale models in calm water and then use the resultant values in the roll equation to predict motions in waves. However, for some wave conditions, the damping coefficients obtained from those tests may not be representative of the actual damping in waves. To assess the influence of wave conditions in the roll damping coefficients, the present work proposes a simplified hybrid approach that combines experimental results from model tests with numerical predictions of roll motion in waves. The numerical tool adopted here is based on a frequency domain single-degree-of-freedom model with linearized external damping that includes viscous effects. A series of experimental model tests with a typical FPSO hull in regular and irregular has been analyzed to obtain the roll damping coefficients in waves. These results are compared with those from decay tests in calm-water as well as from semi-empirical predictions based on Ikeda’s method. Despite the linearized assumption, it is expected that the damping coefficients from wave tests provide a more realistic representation of the roll dynamics than those from typical decay tests.
Development of a Control Strategy for Underway Tandem-Like Oil Transfer Operation Between a Conventional and a DP Tanker
Authors: Moreno Felipe M. , Amendola José , Tannuri Eduardo A. , Ferreira Marcos D. 
Published: November 2019

Abstract
Ship-to-ship (STS) operations have been widely applied for oil and cargo transfer in order to improve operational efficiency and reduce operational costs. Brazil has seen an increase in underway Ship-to-Ship operations due to the lack of available berths and terminals. The transfer operation is carried in sheltered locations in Brazil and abroad, but still has issues such as cable ruptures and high downtimes due to environmental conditions. This work proposes the development and validation of a control system for an innovative configuration for oil transfer between a DP shuttle and a conventional tanker, using a modified tandem configuration. The conventional vessel is underway and the DP vessel follows it with a lateral offset that provides a safe route for escape in case of any failure. The focus of the present paper is the control system design applied to the DP vessel that ensures the safe operation inside the offloading site. This control applies two individual sliding mode controllers for rudder and thruster control, with coefficients obtained from numerical simulations, associated with a line-of-sight strategy for course and speed over ground controllers. The set-point for the controller is obtained from the conventional vessel that is navigating ahead from the controlled vessel. Control performance and operation safety are evaluated through a set of real-time simulations of the transfer operation, where performance is evaluated through measurement of the Bow Loading System point position in both straight line navigation and in a 10km radius curve. The control robustness is evaluated by varying the environmental conditions in the simulations. Safety issues are also considered by evaluating the possibility of evasive maneuvers in case of component failure.
Detection of Mooring Line Failure of a Spread-Moored FPSO: Part 2 — Global Performance Analysis Using MLTSIM
Authors: Kyoung Johyun , Lim Ho-Joon , Sidarta Djoni E. , Tcherniguin Nicolas , Lefebvre Timothee 
Published: November 2019

Abstract
This paper presents Part 2 in the development of an Artificial Neural Network (ANN) model for detection of mooring line failure of a spread-moored FPSO, global performance analysis used to generate the training and test data for the study.
The development of an ANN model for detection of mooring line failure requires a comprehensive training data that is most practically available from the results of numerical simulations. Time domain analysis is necessary to capture the nonlinear behavior of a moored FPSO system and to represent the behavior of the physical system as accurate as possible. Given the wide range of sea-state conditions, of direction of the sea-states and of draft conditions of the FPSO, the number of time domain simulations is easily larger than 100,000. Therefore, an accurate and numerically efficient tool is necessary for carrying this task.
The FPSO hull motion analysis is performed using MLTSIM, a TechnipFMC in-house, nonlinear time domain floating body motion analysis program. MLTSIM captures various non-linear load and response effects such as mooring stiffness, riser loads, drag and drift forces, as well as various user defined loads. MLTSIM is a numerically efficient and fast time domain solver which can run on both high-performance computing (HPC) system and a single laptop.
Numerical model of a FPSO system has been validated using the results of model tests. In addition, the results of numerical simulations, in terms of hull motions and mooring line tensions, are compared with the results of model tests and a commercial software OrcaFlex. This well-calibrated model is then used for generating the numerical data required for the development of the ANN model.
Parametric Rolling in Regular Head Waves of the KRISO Container Ship: Numerical and Experimental Investigation in Shallow Water
Authors: Tello Ruiz Manases , Villagomez Jose , Delefortrie Guillaume , Lataire Evert , Vantorre Marc 
Published: November 2019

Abstract
The IMO Intact Stability Code considers the parametric rolling phenomenon as one of the stability failure modes because of the larger roll angles attained. This hazardous condition of roll resonance can lead to loss of cargo, passenger discomfort, and even (in the extreme cases) the ship’s capsize. Studies as such are mostly conducted considering wave characteristics corresponding to wave lengths around one ship length (λ ≈ LPP) and wave amplitudes varying from moderate to rough values. These wave characteristics, recognised as main contributors to parametric rolling, are frequently encountered in deep water. Waves with lengths of such magnitudes are also met by modern container ships in areas in close proximity to ports, but with less significant wave amplitudes. In such areas, due to the limited water depth and the relatively large draft of the ships, shallow water effects influence the overall ship behaviour as well.
Studies dedicated to parametric rolling occurrence in shallow water are scarce in literature. In spite of no accidents being yet reported in such scenarios, its occurrence and methods for its prediction require further attention; this in order to prevent any hazardous conditions. The present work investigates the parametric roll phenomenon numerically and experimentally in shallow water. The study is carried out with the KRISO container ship (KCS) hull. The numerical investigation uses methods available in literature to study the susceptibility and severity of parametric rolling. Their applicability to investigate this phenomenon in shallow water is also discussed. The experimental analysis was carried out at the Towing Tank for Manoeuvres in Confined Water at Flanders Hydraulics Research (in co-operation with Ghent University). Model tests comprised a variation of different forward speeds, wave amplitudes and wave lengths (around one LPP). The water depth was fixed to a condition equivalent to a gross under keel clearance (UKC) of 100% of the ship’s draft.
A Design Practice for Subsea Pipeline Subjected to UXO Hazards
Authors: Liu Zhenhui , Igland Ragnar , Bruaseth Sindre , Ercoli-Malacari Luca , Lillebø Odd Arne 
Published: November 2019

Abstract
This paper presents a design practice for the oil export pipeline (OEP) of Johan Sverdrup Oil Field subjected to unexploded ordnance (UXO) hazards during the pipeline installation period. The UXO (unexploded ordnance) is a potential risk to the oil export pipeline due to its significant impulsive pressure load in a short time. Present paper discusses an unfavorable scenario in which the UXOs are identified during the pre-lay survey stage. It may (and it does) happen due to the survey methods chosen between the initial preliminary and the pre-lay survey. Consequently the original design pipeline routing has to be updated in order to minimize the UXOs’ potential damage to the pipeline. A safety distance between pipeline and UXOs shall be established and maintained. To achieve this, advanced numerical simulation was used for assessing the damage of pipeline under UXO explosion loads. The damage is sensitive to the charge weight and the distance between charge and pipeline. The pipeline route was updated accordingly based on the safety distance and actual locations of UXOs. The new route shall also fulfill all design checks. With the updated pipeline routing, the installation could continue without interruption of the project schedule. The identified UXOs will be subject to later removal before startup of production to further ensure the safety of installed pipeline. The overall design process is presented. Some simulation results from Abaqus Explicit solver are shown in the paper. Conclusions and discussions are included, which may be useful for similar projects in the future.
Numerical Simulation of Multidirectional Waves With Full-Spectrum Using DualSPHysics
Authors: Kanehira Taiga , Mutsuda Hidemi , Draycott Samuel , Ingram David M. , Doi Yasuaki 
Published: November 2019

Abstract
The numerical model for circular wave basin were developed using DualSPHysics based on Smoothed Particle Hydrodynamics to generate short-crested wave. The recreation of short-crested wave was achieved using Pierson Moskowitz spectrum and cosin2s spreading function with spreading value s. It is found that this numerical tank model could successfully reproduced not only long-crested but short-crested waves using 168 hinged-flap type wave makers.
URANS Simulation of ONR Tumblehome Parametric Rolling in Regular Head Waves
Authors: Zhang Zhiguo , Guo Lixiang , Wang Shuang , Yuan Ye , Chen Can 
Published: November 2019

Abstract
In this paper, an in-house CFD code HUST-Ship is used for the numerical simulation of parametric rolling phenomena of ONR Tumblehome in regular head wave. Preliminary resistance and roll decay simulations at Fr = 0.2 were carried out and compared with existed INSEAN experimental data. Following, three DOFs’ ship motions in regular head wave with an initial roll angle of 30 degrees was calculated to examine the possibility of occurrence of parametric rolling. Finally, a simulation without initial roll disturbance was performed to investigate its influence to the steady roll amplitude. By conducting fast Fourier transform of the time history of motions, forces and moments, the characteristics are analyzed and co-related with wave frequency. Results can be concluded that the in-house code has the ability to perform the parametric rolling simulation, and that the final steady roll amplitude is not affected by the initial disturbance. In addition, heave and pitch motions are dominantly affected by wave characteristic, roll frequency is about half that of wave, and that forces and moments in x direction exhibit high-order non-linearity.
Numerical Modeling Practice and Verification of the Wind Load Estimation for FPSO and Semi-Submersible
Authors: Yeon SeongMo , Jang Hyunchul , Kim Jang Whan , Kim JooSung , Nam Bo Woo , Huang Zhenjia , O’Sullivan Jim , Kim Hyun Joe , Hong Sa Young 
Published: November 2019

Abstract
This paper summarizes a joint effort, TESK JDP, initiated by TechnipFMC, ExxonMobil Upstream Research Company (EMURC), Samsung Heavy Industries (SHI) and Korea Research Institute of Ships & Ocean Engineering (KRISO) in order to develop reliable modeling practices for the application of Computational Fluid Dynamics (CFD) to the design of the offshore floating structures. The modeling practice for the wind load on offshore floating structures, which was one of the topics in this JDP, was studied and verified against model test results.
The wind load on the offshore floating structures mostly depends on the shape of the wind profile rather than the design wind speed. Much weight is put on the generation and retainment of the wind profile within the computational domain. The modeling practice for generating the wind profile referred to as sustainable atmospheric boundary layer (ABL) or horizontally homogeneous turbulent boundary layer (HHTBL) as well as domain size, mesh strategy, turbulence model are used to perform wind load simulations for a semi-submersible and FPSO respectively as a blind test between JDP members. In order to minimize uncertainties from geometric similarity, special care was taken during the simulation and model test for the FPSO due to the complicated top side modules. Given the modeling practice, the results are compared between JDP members and show consistent tendency. Also, a good agreement was observed for the hydrodynamic coefficients of the wind load for both the FPSO and semi-submersible.