bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational Study on the Transmission of COVID-19 Virus Inside a Ship
Authors: Huang Luofeng , Riyadi Seogeng , Utama I Ketut Aria Pria , Thomas Giles 
Published: October 2022

Abstract
To investigate the operational improvements of vessels under the impact of COVID-19, this work has developed a Computational Fluid Dynamics model combined with Lagrangian particles to study the airborne transmission of COVID-19 viruses inside a ship. Initially a generic model was established to enable validation against experimental results for the diffusion of flu virus in an idealised room. Following this, the room geometry was replaced by the superstructure of a full-scale crew boat. Considering the boat advancing in open water, simulations were conducted to study the particulate flow due to a person coughing and speaking, with the boat’s forward door open and closed. The results have shown that, when the forward door is open, a significant airflow can carry the viruses to make extensive contacts with the passengers. This led to the suggestion of keeping the door closed. However, when the forward door is shut, face-to-face speaking can generate viruses that can float in the air for a long time, and it was found that the viruses mainly stay within a half-meter distance in front of the speaking person, before sinking to attach to the deck. Thus, a social-distancing suggestion on seat arrangement has been highlighted to minimise the risk of contagion. Overall, this work is expected to inform guidelines on hygienic and reconfiguring means for operators to counter COVID-19 and potentially the spread of similar viruses in the future.
Rapid Assessment of Ship Bottom Grounding Damage Considering Combined Surge and Heave Motion
Authors: Pineau Jean-Philippe , Le Sourne Hervé 
Published: October 2022

Abstract
In most of the available literature in grounding analysis, the ship is supposed to run aground over a rock following a prescribed horizontal trajectory. However, in situations where the vessel is navigating in presence of waves, its oscillating heave motion sometimes leads to multiple breaches in the bottom plating, as observed in some real grounding events [1]. Recent numerical studies [2] showed that resulting overall damage of the hull can extend up to 4 times the one obtained by assuming only a horizontal movement for the ship.
Despite the increase in computing capacity of computers, nonlinear finite element simulations are very time consuming, and consequently not well suited for probabilistic damage stability analyses that may involve hundreds or thousands of grounding scenarios. In the present paper, a simplified analytical model based on plastic analysis is developed for the response of an unstiffened bottom plating, with the aim to rapidly assess the damage of a ship grounding on a rock idealised as an elliptic paraboloid. At the moment of impact, the ship is supposed to have both heave and surge velocities. Sliding and raking situations are considered and the criterion used to switch from one mode to the other is discussed. The model is then confronted to finite element simulations for different rock shapes, velocities, and friction coefficients. Although the proposed approach is shown to give a good prediction of the dissipated energy in most cases, some limitations are also highlighted.
Flow-Induced Vibration Marine Current Energy Harvesting Using a Centrally-Pivoted Cylinder
Authors: Stappenbelt Brad 
Published: October 2022

Abstract
The phenomenon of vortex-induced vibration (VIV) for elastically restrained cylindrical structures in cross-flows is relatively well investigated. The utility of this mechanism in harvesting energy from marine current and tidal flows is however arguably still in its infancy. With relatively few moving components, a flow-induced vibration based energy conversion device augers low complexity compared to the commonly employed turbine design. Despite the interest in this concept, a practical device has yet to emerge. It is desirable for optimal system performance to design for a very low mass or mass moment of inertia ratio. The device operating range in particular is maximised below the vortex-induced vibration critical point where an infinite resonant response region is realised. An unfortunate consequence of this requirement is large buoyancy forces that need to be mitigated by gravity-based, suction-caisson or anchor mooring systems. The focus of this paper is the testing of a novel VIV marine current energy-harvesting configuration that utilises a centrally-pivoted horizontal cylinder. The results of experimental investigations, utilising the University of Wollongong fluid mechanics laboratory towing tank, are analysed and presented. A reduced velocity test range of 0 to 27 was covered. Power take-off (PTO) damping ratios spanning from 0.041 to 0.392 were examined in order to determine the optimal conditions and hence the maximum device energy conversion efficiency.
Solitary Wave Propagation Using a Novel Single Fluid Finite Volume Method for Free Surface Gravity Waves
Authors: Roland Kjærgaard Qwist Jesper , Christensen Erik Damgaard 
Published: October 2022

Abstract
Accurate prediction of wave loads from extreme waves on individual beams in offshore jacket structures are important to ensure the structural integrity. As the load distribution along a beam is strongly tied to the wave kinematics it is crucial to have an accurate prediction of the surface elevation and the velocity field.
The open-source CFD code OpenFOAM contains two solution algorithms (interFoam and interIsoFoam), which are used for ocean wave simulations and wave load predictions. The algorithms are often applied using a too coarse spatial discretisation, which violates the assumption of a continuous solution at the free surface. The consequence is inaccurate and unphysical predictions even for propagation of a steady wave.
Our recently developed Direct Surface Description (DSD) solution algorithm in OpenFOAM is used to simulate a solitary wave with different cell aspect ratios. The solitary wave case shows that the DSD method provides accurate velocity fields and surface elevations both for square and horizontally elongated cells.
Comparison of Cutter Suction Dredger Slurry Concentration Soft Measurement Method Based on the Mechanism and Data Dual-Driven Model
Authors: Wang Bin , Fan Shidong , Xiong Ting , Zhu Hanhua 
Published: October 2022

Abstract
Aiming at the problem that the cutter suction dredger (CSD) slurry concentration measurement method (γ-ray concentration meter) is single, and the frequent failures affect the construction continuity. A soft measurement method of slurry concentration based on the mechanism and data dual-mode drive was proposed. First, analyze the process of cutter cutting and the force of the mud and sand particles inside of the cutter. Then, the concentration prediction model of the slurry transportation process was presented by digital simulation modeling technology. Second, a data-driven slurry concentration prediction model was established, using big data, machine learning, data mining, and other technologies, which learn the historical data of the dredger. To verify the accuracy of the two models, this paper designed three different parameters and five operating conditions on the experimental platform. Experiments show that the prediction performance of the two models is good. In most working conditions, the mechanism-driven slurry concentration model and the data-driven slurry concentration model maintain an error rate of less than 5%, but the prediction error of the mechanism-driven slurry concentration model is relatively large under the flow velocity at the suction port is 3.5 m/s.
Overall, the slurry concentration prediction model based on the mechanism & data has high prediction accuracy and can improve construction efficiency and reliability.
Subsea Buoyancy and Gravity Energy Storage System for Deep-Water Applications: A Preliminary Assessment
Authors: Novgorodcev Andre R. , Mols Frank , Jarquin Laguna Antonio 
Published: October 2022

Abstract
This article presents a preliminary assessment of a subsea buoyancy and gravity energy storage system (SBGESS). The storage device is designed to power an off-grid subsea water injection system to be installed at the Libra oil field in Brazil at 2000 m below sea level. Two 12MW floating wind turbines provide the energy supply. The system performance is evaluated according to historical wind data from reanalysis models, the water injection pumps’ power curves, the required daily water flow rate, and the maximum number of shutdowns allowed per year. A control strategy with three different operation modes and one energy-save sub-mode was implemented to optimise the size of the proposed energy storage system.
Effects of Rheological Properties on Primary Cementing of Irregular Horizontal Wells
Authors: Sarmadi Parisa , Frigaard Ian A. 
Published: October 2022

Abstract
Primary cementing is an industrial operation that is used to seal every oil and gas wells, of which there are many millions globally. The process aims to remove the drilling fluid and other residues from the annulus between the casing and the formation, replacing it with a cement slurry, which then hydrates and seals the well to prevent subsurface leakage. Leakage compromises well productivity and can have environmental and health consequences, e.g. polluted aquifers, methane emissions, and subsurface ecosystems. In this work, we focus on fluid displacement mechanics of primary cementing operations. Even in stable boreholes, several geometrical and operational irregularities can be seen while reading caliper data. Washouts, keyseats, and breakouts are examples of irregularities. The other irregularity arises from eccentricity which mainly originates from operational features. Eccentricity of the annulus significantly affects the cement placement flow and longevity of the wellbore.
In this work, we study the effect of the rheological properties of fluids involved in the primary cementing on displacement flows in an irregular horizontal section of well. The focus of the work is on irregularities in the shape of enlargements. We use three-dimensional (3D) numerical simulations, using the Volume of Fluid (VoF) method to compute displacement of a drilling mud by a spacer within an annulus with series of enlargements. We use Bingham fluid and Newtonian fluid models for the mud and spacer, respectively. The 3D model allows us to capture the interface between fluids and study the effects of more local irregularities in detail, e.g. secondary flows and residual mud layer on the wall of the well. The rheology of the fluids beside the geometrical properties, irregularity and eccentricity, plays important role in determining the presence of unyielded residual mud layer. In this paper we describe the competition between viscosity ratio and density differences with geometrical properties.
Peridynamic Analysis of Floating Ice Under Transverse Pressure
Authors: Bachimanchi Pranitha , Saha Nilanjan 
Published: October 2022

Abstract
Offshore structures frequently interact with floating ice during its operational conditions in the arctic region. The structures are mainly designed in a slopping manner such that vertical loads are exerted, leading to out-of-plane failure of floating ice. In [1], the fracture pattern and failure process of ice floe with different dimensional conditions are studied through the classical approach. In the present study, a peridynamic approach has been adopted to analyze the fracture pattern of floating ice. Peridynamics [2] is a modified continuum mechanics that reformulates classical governing equations by replacing spatial derivatives with integrals. The main advantage of the novel approach is the incorporation of damage within governing equation. Unlike the classical method, it treats crack as an internal part of the body, eliminating the need for external kinetic relations to analyze crack growth. In [3], the peridynamic model of floating ice has been presented. Also, the crack growth pattern under transverse load with a pre-existing crack is studied. The current study validates the peridynamic model of floating ice, modeled as a peridynamic Mindlin plate [4] resting on Winkler elastic foundation [5] (representing sea surface), under static transverse pressure with classical theory. Then, the fracture pattern of the floating ice with and without pre-existing crack is studied and validated with the available literature.
Prediction of Structural Damages and Armament Accelerations of a Surface Naval Ship due to Underwater Explosions
Authors: Kim Hyunwoo , Cerik Burak Can , Choung Joonmo 
Published: October 2022

Abstract
Underwater explosion (UNDEX) caused by torpedoes yields the largest subsurface load that can be applied to a naval surface ship. The purpose of this paper is to estimate the extent of structural damages and accelerations acting on major armament systems by UNDEX for a large naval surface ship. The hull of the naval surface ship was modeled using Abaqus, a commercial finite element analysis code. By applying the Geers and Hunter UNDEX model provided by Abaqus, the primary shock wave and the secondary bubble wave based on doubly asymptotic approximation were implemented. The DSSE-HC model (Hosford-Coulomb combined with a localized necking model) enhanced for strain-rate effect was applied to estimate the extent of structural damages caused by UNDEX. Since the DSSE-HC model is not supported by Abaqus, the material subroutine was independently developed. The range of structural damages predicted by the DSSE-HC model was compared with that predicted by the constant failure strain model, which is widely used for UNDEX problems, to identify a difference in the structural damage. As a result, it was confirmed that there is a large difference in resulting damage. That is, the constant failure strain model predicted overestimated the extent of damage depending on the assumed failure strains. In addition, the accelerations acting on the various armament systems also showed significant differences. To predict the structural damage and acceleration of the armament system due to a UNDEX in the future, it was found that it is necessary to apply a fracture model with an advanced mechanical background rather than a simple fracture model.
The Long-Term Stress Range Distribution of Marine Risers Considering the Effect of Wave Directionality
Authors: Haghayeghi Zohreh Sadat , Ketabdari Mohammad Javad 
Published: October 2022

Abstract
The long-term distribution of stress cycles is a crucial part of the fatigue life assessment of offshore structures. This research studies the wave and current induced motion of a top tensioned riser connected to a semi-submersible platform. To account for the directionality, the platform’s directional response amplitude operator (RAO) is applied.
Since this research aims to calibrate Weibull distribution parameters, a long-term analysis of stress cycle distribution for all sea states is run. A finite element model is developed to solve riser dynamics under the effect of waves, currents, and top vessel motions. The code is solved for 87 sea states in the time domain, and then the stress cycles are derived by the Rainflow counting method. Finally, the long-term stress ranges distribution is fitted to a Weibull distribution. Comparison of the results in cases with and without directionality, shows that directional assumption leads to a broader distribution for stress ranges.
Knowledge Elicitation and Digitization Using FRAM to Inform Automation of Marine Operations in Ice
Authors: Musharraf Mashrura , Smith Doug , Smith Jennifer , Veitch Brian 
Published: October 2022

Abstract
Autonomous systems are becoming more common in the maritime industries. Some marine operations are more straightforward to automate than others. For example, the navigation of local vessels can be more easily automated on account of well-established standard operating procedures and relatively predictable operating conditions. Complex operations, such as ice management for ocean going ships, are less amenable to automation. Ice management is complex in nature and often takes place under challenging circumstances that include harsh weather, time constraints, and multiple information sources. The conditions are dynamic, and it is difficult to predict precisely how the circumstances will evolve. Successful ice management depends both on prior managerial planning and on-the-job adjustments made by the seafarers in dynamic operational conditions. To reach the level of autonomy equivalent to expert seafarers, the machine needs to assess, reason, decide, and act like them. One way to achieve this is to train the machine by the experts. This paper presents how the Functional Resonance Analysis Method (FRAM) can facilitate such training by connecting the human (expert seafarers) and the machine. A FRAM model of the ice-management operation will be used to 1) understand the ice management operation from experts and visualize it, 2) identify the salient features used and the on-job-adjustments made by experts during the operation, and 3) guide the digitization of the collected knowledge for ice-management automation.
Energy-Maximising Control Philosophy for a Cyclorotor Wave Energy Device
Authors: Ringwood John V. , Ermakov Andrei 
Published: October 2022

Abstract
Recently, cyclorotors, utilizing lift rather than buoyancy forces for energy extraction, have been proposed and inherit many of the appealing features characteristic of modern wind turbines. In particular, the ability to spill energy though foil pitching allows the device to remain at rated power despite significant variations in input power level, while additional cyclorotor features, including variable submergence depth and rotor radius, also permit a significant degree of modulation of the device structure, and energy absorption characteristics, offering considerable flexibility. These configuration flexibilities, in addition to torque control of the rotor/generator shaft (also characteristic of wind turbines) offers the control engineer considerable freedom in adjusting the device characteristics to maximise the effectiveness of the device in capturing wave power, while maintaining structural integrity and minimizing harmful stresses on system components. However, such flexibility also provides a significant challenge in the form of a multivariable control problem for a system described by significantly nonlinear hydrodynamics. This paper describes a proposed hierarchical control system for a cyclorotor wave energy device, utilizing submergence depth, rotor radius, foil pitch angles, and shaft torque as control inputs. The hierarchy involves the separation of the control actuators into two classes: structural (or slow) control effectors, and wave-by-wave (or fast) control effectors. In particular, the paper will examine the interaction between the two levels of the control hierarchy and the need, if any, for simultaneous optimisation of the control parameters at both levels.
Geohazard Study of Mudslide Event at a Subsea Escarpment and Structural Response of Crossing Flowlines: Part I – FEA Analysis
Authors: Hayes Kevin , Jang Hyunchul , Lai Lawrence , Musto Anthony 
Published: October 2022

Abstract
Subsea earthquakes have the potential to cause mudslides on the seafloor. These extreme events can have a significant impact on the structural integrity of subsea flowlines and umbilicals. A numerical geohazard study is performed on a subsea mudslide event occurring at an escarpment. The study objective is to determine the structural response of flexible lines crossing the escarpment area when subjected to an extreme mudslide event and to determine both the survivability of the lines and the need for proposed anchoring devices.
The study utilizes several numerical methodologies of increased complexity, precision, and cost, such as Finite-Element-Analysis (FEA), Computational-Fluid-Dynamics (CFD), and Fluid-Structure-Interaction (FSI).
This paper focuses on the FEA analysis, with the CFD and FSI analyses presented in a separate paper [1]. The FEA methodology reduces conservatism over conventional approaches by applying the mud debris flow effects on the flexible lines with a one-way CFD to FEA coupling and a morphing escarpment bathymetry. A CFD simulation is performed on a rigid seabed bathymetry to extract the mudslide velocity field at every second. This velocity field is applied to the Abaqus FEA simulation using Abaqus/Aqua with a one-way coupling approach, thereby allowing the FEA model loading on the flexible flowlines to be updated from the load created by the mudslide motion.
A key finding from the FEA study is that although the mudslide event creates large displacements in the flexible lines, it does not significantly pull the flexible flowlines over the escarpment, thereby eliminating the need for planned anchors and saving significant capital expenditure and installation costs.
Artificial Neural Network Surrogate Modeling for Offshore Wind Turbines Under Multi-Hazards
Authors: Wang Xiaowei , Heo YeongAe 
Published: October 2022

Abstract
Surrogate modeling of offshore wind turbines (OWTs) under multiple hazards such as wind, wave, and earthquakes provides an expedient path toward rapid risk assessment and management of these structures. This paper explores the applicability of artificial neural network (NN) for the surrogate modeling using a synthetic database based on finite element analyses of a typical OWT under combined loading conditions due to winds, waves, and earthquakes. A multi-layer NN with multiple output variables that can effectively capture the OWT’s multi-hazard behavior is developed. Considered input variables include peak ground accelerations, reference wind speeds, wave heights and periods, and damping ratios. A 5-fold-cross-validation-based optimization is conducted to identify the optimal number of hidden layers (N) and the associated optimal number of neurons in each layer (Q). It is found that N = 2 and Q = 12 are optimal for the OWT. The proposed NN model can evaluate the monopile maximum bending moment, and displacement/rotation at mudline with errors less than 30% in general.
Three-Dimensional Simulations for Geometric Optimization of a Shoreline Hybrid Wave Energy Converter
Authors: Koutrouveli Theofano , Das Neves Luciana 
Published: October 2022

Abstract
Hybridisation of different wave energy conversion (WEC) technologies appears to be a promising approach to harness the available wave energy resource most efficiently over a wide range of metocean conditions and overcome some of the challenges facing the roll out of a competitive wave energy industry. This underlying idea, hybridisation, is in the genesis of a novel device being further developed in the OCEANERA-NET project WEC4PORTS, which had been proved under the SE@PORTS project. Said novel hybrid wave energy converter (HWEC) combines two well-known wave energy conversion principles, an oscillating water column (OWC) and a multi-reservoir (4 reservoirs in the present configuration) overtopping device (OTD) and has been developed for installation in multipurpose breakwaters — i.e., a structure that retains its primary function of providing sheltered conditions for port operations to develop and includes electricity production as an added co-benefit. In this paper focus is given to the three-dimensional numerical model developed with OpenFoam for comparing alternative configurations of this breakwater-integrated HWEC, by studying the hydrodynamic efficiency. In total, five alternative geometries were compared. A frequent sea-state off the northern Atlantic coast of Portugal near the northern outer rubble-mound breakwater of the port of Leixões — the research prototype — is considered.