bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Stochastic Approach to Short-Term Ocean Wave Forecasting: Preliminary Results Using Data From a Remote Sensing Imaging System
Authors: Mérigaud Alexis , Tona Paolino 
Published: October 2022

Abstract
There is a growing interest in the applications of real-time wave forecasting (RTWF), which consists in predicting physical quantities directly related to waves, such as the free-surface elevation, wave loads, or the motion of a ship, from a few seconds to several minutes in advance, and using measurements updated in real time. Unlike comparable RTWF methods found in the literature, which are based on the solution of the physical wave propagation equations, the present approach, known as SBP (Spectrum-Based Predictor), adopts a rigorous probabilistic view on the wave prediction problem, based on well-established, standard oceanographic assumptions. This paper presents an application of the SBP method to real wave field data coming from a stereoscopic camera system. To the best of the authors’ knowledge, this is the first time stereo wave data are employed to test RTWF algorithms. The data, recorded at a location in Korea, in the Yellow Sea, present some considerable challenges, such as strong current in excess of 1 m/s, steep waves with substantial non-linear components, and large directional spread in the high-frequency range. With some adjustments to the original SBP approach to account for current, several prediction configurations are tested, showing excellent agreement between the experimental prediction performance curves, and those expected from the SBP theory. With an observation range in the order of 100m, and in the wave conditions studied, reasonably accurate predictions can be achieved up to 20s ahead (approximately 3.5 peak wave periods).
Automated Modal Parameters Identification During Ice-Structure Interactions
Authors: Wang Chunlin , Nord Torodd Skjerve , Li Guoyuan 
Published: October 2022

Abstract
Offshore structures are prone to damage caused by ice-induced vibrations. It is presently unknown to what extent different ice conditions change the properties of the structure, such as natural frequency, damping ratio, and mode shape. Understanding the dynamic interaction between ice and structures are important for the operational ability of offshore structures. In this study, the covariance-driven stochastic subspace identification algorithm (SSI-cov) is introduced to identify modal parameters of a scale-model structure during ice-structure interactions. In order to reduce the number of user interactions and inherent bias to the identified modal parameters, we therefore introduce an automated parameter identification approach. First, SSI-cov is used to obtain poles that describe the information: damping ratio, mode shape, etc. After that, a stable criterion is used to pick up stable poles. Finally, Hierarchical clustering is used to cluster poles to identify the natural frequency. The proposed method is able to reduce the many user-intervenes and enables efficient automatic parameter identification. The results show that Hierarchical clustering can render more successful identifications than the slack value-based method among different ice speeds. The results also show changes in the system frequencies for different ice conditions.
Seakeeping Analysis of a GRP Fast Patrol Vessel
Authors: Hydar V. , Boote D. , Vergassola G. , Păcuraru F. 
Published: October 2022

Abstract
In order to convert the “one-off” construction of light alloy fast boats to a more efficient series production, the project of a 25-meter patrol boat, originally built in aluminum, has been completely reviewed, focusing on the structure design in composite material.
As one of the most important targets of the new project is to further increase the speed performance of the original unit, attention has been initially focused on the weight reduction, this goal being particularly challenging because of the change in the construction material. This gave the opportunity to review the design parameters as well, starting from the design acceleration value which has been assessed at first by considering the Classification Society Rules and secondly by a detailed seakeeping analysis carried out by using ANSYS AQWA software and validated by experimental towing tanks tests at MARIN.
Shallow Water Nonlinear Waves: Their Wave Equations, Quasiperiodic Fourier Series Solutions and Statistical Distributions
Authors: Osborne Alfred R. , de Pinho Uggo F. , Kvingedal Børge , Lian Gunnar 
Published: October 2022

Abstract
The goal of this paper is to bring new mathematical and physical methods to the problem of shallow water wave motions, for which there are many important engineering applications. There are four issues we address in this paper:
(1) Nonlinear integrable wave equations have (quasiperiodic) Fourier series solutions. This means that, even though the wave dynamics are nonlinear, they can nevertheless be described as a linear superposition of sine waves, a surprising result. Nonlinearity arises from particular phase locking of the Fourier modes.
(2) We discuss how these Fourier series solutions can always be computed to high accuracy for a particular nonlinear wave equation. While quasiperiodic Fourier series are more complicated than ordinary periodic Fourier series (a standard tool of ocean engineering as the Fast Fourier transform, or FFT), the advantage of dealing with a linear superposition law for nonlinear equations is quite useful.
(3) We apply these Fourier series to the modelling of water waves. Amazingly, we use the linearity property of the quasiperiodic Fourier series, and we find a new wave model for solving nonlinear wave motion. Our model, which we call quasilinear, has properties similar to the well-known linear model already applied to ocean engineering problems for over 90 years [Paley and Weiner, 1935] [Longuet-Higgins, 1957]. An additional particular transformation (due to Baker [1907], Its & Matveev [1976], Mumford [1982]) to the quasilinear model allows us to simply simulate typical oceanic nonlinear wave motions and to analyze data.
(4) We discuss determination of the important probability distributions of water waves for amplitudes, heights and crests from knowledge of the quasiperiodic Fourier series solutions.
The results given herein are based upon a simply stated
Theorem: Given an integrable wave equation and/or its Hamiltonian perturbations we can write the full spectral solutions of the equations as quasiperiodic Fourier series and we can also analytically determine the probability distributions of various properties of the wave field (including, amplitudes, crest heights and wave heights).
We are interested in shallow water wave motion in the present paper and our nonlinear wave equation of choice is the Korteweg-deVries equation (KdV). Our simple discussion has therefore introduced quasiperiodic Fourier methods and probability distributions to the solutions of the KdV equation. Furthermore, the Kadomtsev-Petviashvili equation is a two-dimensional shallow water wave equation (a generalization of the KdV equation, also with Hamiltonian perturbations) and it too can be treated in a similar manner. In this context this paper is dedicated to a discussion of important physical and engineering tools for the shallow water domain.
Moment Loads on a Two-Dimensional Turret-Moored Vessel Under Forced Motion
Authors: Tong Feifei , Wolgamot Hugh , Draper Scott 
Published: October 2022

Abstract
This paper investigates the moment loading and heading response of a turret-moored vessel subjected to surface currents using two-dimensional Computational Fluid Dynamics. To investigate the hydrodynamic loads on the vessel, the moment load was first calculated when the vessel was held fixed at different headings such that the angle between the long axis of the vessel and the current ranged from 0° to 360°. At any fixed angle of attack, the moment load showed nonlinear time-dependent behaviour, where the amplitude of the load is larger at angles when the ship is aligned normal to the current (approx. 90° to 120°). The instantaneous moment is dependent on the vortex flows around the structure. Following this, the vessel was modelled with one rotational degree-of-freedom and forced to rotate at a fixed angular speed. Several angular speeds were simulated, indicating that the moment loads correlate with the ratio of the steady current velocity to the linear velocity of the vessel at its far end. These comparisons illustrate the complex dynamics of forces with and without vessel rotation. Ongoing work will compare these results to predictions based on a simplified dynamic model for the vessel heading and extends the results to a three-dimensional vessel, where the dynamics remain complicated, but the role of vortex shedding is less significant.
Numerical Simulation of Hybrid Synthetic Mooring Lines Based on a Finite Difference Dynamic Model
Authors: Li Xinyi , Yu Liwei , Wang Shuqing 
Published: October 2022

Abstract
For the deep-water mooring, the hybrid synthetic mooring lines (with chain-rope-chain configuration) are often used for their advantages in weight and cost against full steel chains. In this research, a finite difference dynamic model is developed for numerical simulations of hybrid synthetic mooring lines. The simulation model is validated by the single steel chain model experiments and “chain-rope-chain” mooring line simulations. Then, the validated model is used for the dynamic analysis of two mooring systems with 4 and 16 hybrid synthetic mooring lines. From the dynamic stiffness iteration of two mooring systems, it is found that the top tensions of the mooring lines arranged symmetrically about the y-axis has a phase difference of half a cycle, and their dynamic stiffnesses are very close. For the mooring system with “4 × 4” hybrid synthetic mooring lines, it is found that the smaller the angle between the mooring line and x-axis is, the larger change in top tension, and the smaller axial stiffness becomes, and the axial stiffness tends to a certain value as the number of iterations increase.
Cross Section Analysis of Flexible Risers Including Composite Layers
Authors: Skeie Geir , Sødahl Nils , McGeorge Dag 
Published: October 2022

Abstract
Oil and gas exploration and exploitation in deep and ultra-deep waters challenges classical riser technology and configuration. New technologies, including carbon fiber as composite armors, influence weight and strength of the riser. This can allow for more simple configurations compared with conventional ones, simplifies installation procedures and eventually lead to reduced costs. The new fiber reinforced cross section sheaths requires new analytical models in the local stress analysis tools. The current paper explores efficient and accurate implementations of orthotropic laminate sheaths into classical cross section simulation tools. The model is based on a classic partition of the analysis scheme into a combined load and response model consisting of an axisymmetric and pure bending part. The suggested model is based on full 3D elasticity solution that allows for thick cylindrical laminates taking into account all stress and strain components. The model is compared with 3D Abaqus results for a number of different lay-ups and the results show excellent agreement with the more advanced 3D simulations in both axisymmetric and bending response modes. The laminate, a thermoplastic composite layer with carbon fibers, is used as a component in an unbonded flexible pipe. The cross-sectional analysis is thus performed in the classical way.
Vessel-Less Underwater Inspection at Fixed Offshore Structure by Utilizing Mini Remotely Operated Vehicle (Mini-ROV)
Authors: Chong Dave Chen Lung , Suhaili Ave Suhendra , Ng Sok Mooi , Wan Shafie Wan Hariz Fadli , Isnadi Biramarta , Khan Riaz , Lau Kheng Hoong , Hassan Nurzarina , Ismail M. Faqrudin B. 
Published: October 2022

Abstract
Mini Remotely Operated Vehicle (mini-ROV) technology has been utilized to perform underwater inspection with optimized Risk-based Underwater Inspection (RBUI) scope for offshore platforms which conventionally utilize divers and ROV supported by Dynamic Positioning II Diving Support Vessel (DPII DSV). This offshore technology was introduced by launching mini-ROV from platform deck to perform General Visual Inspection (GVI), Cathodic Potential (CP) Survey, Flooded Member Detection (FMD) & Ultrasonic Thickness (UT) measurement with customized mini-ROV integration with other tooling. The small size ROV is light and easy to handle by technician onboard platform deck. It is also capable to enter congested areas as it is easily maneuvered, which help to capture close visual of the findings. During emergency, the mini-ROV can be mobilized instantly at site to support any GVI related scope. PETRONAS has successfully deployed this technology at four platforms in one of the operating regions from 2017 to 2021 with cost saving of 30%–50% compared to conventional method. The successful implementation in PETRONAS can become benchmark and reference for other Oil & Gas operators as an alternative to conduct optimized RBUI scope which can contribute to lower Operating Expenditure (OPEX).
Mooring Fatigue Damage Prediction Based on Importance Sampling
Authors: Okkenhaug Siril , Merino Hoyos Daniel , Magnussen Eivind Tørset , Macke Michael 
Published: October 2022

Abstract
DNV is currently running a Joint Industry Project, “NorMoor JIP”, which is now approaching the end of phase 3. In this phase the fatigue limit state (FLS) of mooring line studless chains for permanent units has got the main attention. Phases 1 and 2 covered the ultimate (ULS) and accidental limit states (ALS), respectively. It is a global study covering Gulf of Mexico, Northern Europe and Brazil waters.
The focus in the present paper is on more accurate mooring line fatigue damage prediction using the entire environmental database in an efficient way. The environmental model applied in mooring fatigue analyses is developed from an environmental database relying on measurements and/or hindcast models. Traditionally, mooring fatigue analyses have been based on scatter diagrams, extracted from this database. More recently, an alternative method is to apply an entire calendar year in the calculations, and the selected year is the one which is assumed to produce the average yearly damage corresponding to the complete environmental database. Both options imply a set of assumptions which are challenged in this paper.
As part of NorMoor JIP, DNV has also developed a new fatigue analysis methodology based on importance sampling of the environmental database. This methodology is both accurate when benchmarked against the analysis of the complete database and effective in terms of computational effort. In addition, an estimation of the statistical error of the calculation is obtained.
A series of 3 papers is published at the OMAE2022 documenting the work done in the NorMoor JIP Phase 3 on the fatigue limit state of mooring lines. Additional to the importance sampling method in the present paper, the OMAE2022-81465, provides statistical analysis results of a comprehensive database of fatigue test data. Furthermore, in OMAE2022-81463 the structural reliability analysis and code calibration is presented and recommendations for a revised fatigue design analysis procedure for FLS of mooring lines is given.
Solutions to Wave Damping Over Time in CFD RANS Simulations Due to Exponential Generation of Numerical Turbulence
Authors: Casalone Pietro , dell’Edera Oronzo , Fontana Marco , Mattiazzo Giuliana , Battisti Beatrice 
Published: October 2022

Abstract
In ocean engineering, high-fidelity analyses like computational fluid dynamics Unsteady Reynolds Averaged Navier Stokes simulations are fundamental for the evaluation of realistic hydrodynamic loads during extreme events, which are usually overestimated by boundary element method based solvers, thus leading to the definition of an oversized wave energy converter structure. To describe multiphase flows, the most used model in RANS CFD simulations is Volume of Fluid model, which consists in creating an interface between the different fluids and assigning to each cell of the domain a percentage of each phase. Unfortunately, the model has a well-known problem in the ocean engineering community which increases with simulation time and affects the wave propagation. For the correct spatial propagation of the wave motion, it is necessary to use a very low Courant-Friedrich-Lewy factor, hence causing a noticeable increase in the computational time and speeding up the generation of artificial turbulence in the domain. The problem is intrinsic in the Volume of Fluid model and cannot be solved by refining the mesh or increasing the order of accuracy of the solvers. The numerical turbulence spreads in the whole domain and dampens the waves overtime after several wave periods (10–50).
With this work, we analyse the effect of a threshold on the turbulent viscosity to reduce the production of numerical turbulent kinetic energy; theaim is to produce a general methodology to simulate long time frames in a RANS simulation with the Volume of Fluid model.
The investigation is first performed in a semi-2D tank by monitoring the wave probes over time. It is then repeated in a 3D domainwith and without the limiter in the case of a floating body, to verify that the kinematics of the floater is not altered by the limiter.
Man-Portable Hybrid Unmanned Underwater Vehicle With High-Bandwidth Wireless Communication
Authors: Immas Alexandre , Fong Chong Hang , Sung Rebecca , Liao James , Alam Mohammad-Reza 
Published: October 2022

Abstract
Commercial underwater robotic vehicles can be categorized into Remotely Operated Vehicle (ROVs) connected to a support vessel with a tether or Autonomous Underwater Vehicles (AUVs) pre-programmed to fulfill a mission. We present in this work a man-portable Unmanned Underwater Vehicle (UUV) which is semi-autonomous, thus contributing to fill the gap between the two extreme levels of autonomy at which ROVs and AUVs operate. We define semi-autonomous operations as autonomous operations supervised in real-time by a human operator who can interact with the UUV at any time to conduct a specific task or to change the UUV’s mission. This type of operations is enabled by hybrid capabilities, defined as a UUV’s ability to be remotely operated or autonomous, and by high-bandwidth wireless communication to allow a human operator to supervise and interact with the UUV. Path following capabilities are provided to the UUV by implementing an Adaptive Feedback Linearization Controller in its autopilot firmware. The resulting hybrid capabilities and the performance of the control scheme are presented using a Software In The Loop simulator. High-bandwidth wireless communication is achieved by equipping the UUV with a LED modem and a Pan-Tilt system to maintain Line of Sight communication with another stationary LED modem connected to a topside station. Experimental tests in a wave tank showed that a 3.5Mbps full duplex wireless optical link could be set up over 7m and maintained despite the motion of the UUV.
Applying Open Web Architectures Towards Collaborative Maritime Design and Simulation
Authors: de Oliveira Felipe F. , Fonseca Ícaro A. , Gaspar Henrique M. 
Published: October 2022

Abstract
This work investigates the use of open architectures to support the development of flexible and scalable maritime design web applications, giving stakeholders shared access to data. It turns to the popular full-stack MERN architecture (MongoDB, Node.js, Express, and React), which is is modular and mostly open source. A prototype web application providing features for ship design and operation was developed. The app stores a ship model which can be linked to different analyses and simulations. During design, users might opt to visualize the model of the ship with a spatial view; during operation, they can resort to a detailed visualization displaying the vessel as built. Three examples are provided to illustrate the potential of these features. First, a dashboard displaying results for hydrostatics, stability, resistance, and motion response. The second use case hypothesizes a vessel is set to undergo a jumboization procedure and compares the analyses results for the vessel after elongation with the current ones. The third exemplifies how a preliminary maneuvering model can be confronted with results from a sea trial by linking the app to operational data, a step towards digital-twin concepts. The discussion addresses the potential of the approach and challenges that need to be considered before extending it to an application that can be used outside the academia.
New Approach to Predict the Filtrate Invasion of Nanoparticle-Based Drilling Mud Using Artificial Neural Network
Authors: Gasser Moamen , Naguib Ahmed , Mahmoud Omar 
Published: October 2022

Abstract
During drilling of hydrocarbon reservoirs, loss of mud filtrate into the formations occurs due to the difference between mud hydrostatic and formation pressures. Filtrate invasion is a vital parameter that should be optimized to reduce formation damage. Recently, nanoparticles (NPs) — among different additives — have been thoroughly examined to minimize mud invasion and showed promising performance. Modeling the impact of NPs on the filtrate loss can fasten the process of selecting their optimum type, size, concentration, etc. to meet the drilling conditions.
In this work, artificial neural network (ANN) was used to develop a model that can predict the filtrate invasion of nano-based mud under wide range of temperature and pressure up to 350 °F and 500 Psi, respectively. Seven types of nanoparticles with size and concentration ranges from 15 to 50 nm and 0 to 2.5 wt%, respectively, have been included in the model. Almost 2,863 data points were used to develop the ANN-model. Experimental work was conducted to collect 806 data points, whereas the rest were collected form the literature. The data set was divided into 70% for training and 30% for validating the model. A total of 6,750 different combinations for the model’s hyperparameters were evaluated to select the optimal combination. N-encoded method was used to convert the categorical data into numerical one. The model was evaluated through calculating the statistical parameters.
The developed ANN-model showed high accuracy for predicting the filtrate loss at different pressures and temperatures. The obtained results showed that the average absolute relative error (AARE) is less than 0.5%, and coefficient of determination (R2) is more than 0.99 for the overall data. The developed ANN-model covers wide range of pressures and temperatures. Moreover, it covers various NPs’ types, concentrations, and sizes, which confirms its useability and coverability.