bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Modelling and Optimal Control of a Hybrid Propulsion System for an Ice-Capable Ship
Authors: Zhou Yi , Pazouki Kayvan , Norman Rose 
Published: November 2019

Abstract
Due to the effect of global warming, navigation on the Northern Sea Route (NSR) has become a more economical and reliable choice for international cargo transportation. In some ways, global warming has increased the opportunity of shipping activities in the Arctic region and hence the need for ice-capable vessels. NSR shipping provides benefits for international trade, but challenges still exist. Although conventional direct drive propulsion system connected to 2 stroke marine engine is normally considered the most efficient approach for long-range transport, for icebreaking operation which requires prime movers to work at partial load, conventional mechanical propulsion systems generally have poor fuel efficiency and high emissions. Moreover, the harmful gases produced by ships trading in NSR have a significant impact on the Arctic climate. Moreover, a traditional mechanical drive icebreaker with a diesel engine is required to operate at high torque, low rpm during icebreaking operation. Thus conventional diesel engine that isn’t optimised to operate at this point would be inefficient and would produce black carbon due to incomplete combustion, which has the potential to cause ice, snow, and cloud albedo out of proportion with normal pattern, thus lead to serious impacts on the Arctic environment and eco-system. Arctic ship propulsion systems have been developing since the 19th century, with modifications such as the use of diesel electric propulsion systems and nuclear power propulsion systems which can ideally meet the requirements of ice breaking operation (low speed and high torque), however, drawbacks still exist in these systems, such as poor fuel efficiency at low speeds for diesel electric propulsion and for nuclear power, there are limitations such as high initial cost, management of nuclear waste and the fact that the required deep knowledge of nuclear technology is mastered by few countries. Hybrid propulsion is a new technology for ice-capable ships, which can address the partial loading efficiency problem in diesel-electric propulsion by charging and discharging a battery energy storage unit which can allow the ship to work in zero-emission mode in some sensitive areas. In this paper, detailed modelling, primary control strategies (voltage and frequency stability) and efficiency analysis of system components such as the motor, generator, battery and conversion devices etc. are and implemented in software, and then the whole power system is simulated with a secondary control strategy (load power sharing and battery aging concern) in both ice and open water load conditions. The results from the diesel electric system and hybrid system total fuel consumption within a target journey are compared to investigate the advantage of the hybrid system, which show up to a 40% fuel consumption reduction for hybrid propulsion arrangement. A tertiary control strategy for energy management is analysed and implemented in the system to further reduce system fuel consumption.
Experimental and Numerical Investigations on Wave Dynamics of a Dual-Chamber OWC Wave Energy Device
Authors: Ning Dezhi , Wang Rongquan , Teng Bin , Zou Qingping 
Published: November 2019

Abstract
Oscillating Water Column (OWC) wave energy device is one of the most studied and applied wave energy converters (WECs). The survivability of WECs is a major concern in the OWC design. In this study, the wave dynamics of a dual-chamber OWC device is numerically and experimentally investigated. The experimental tests were carried out in the wave-current flume at the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. A fully nonlinear numerical wave flume based on potential-flow theory and time-domain higher-order boundary element method (HOBEM) is developed and applied to simulate the interaction between air, wave and the dual-chamber OWC device. The numerical model is validated by comparing the simulated wave induced pressure on the barrier walls with the measurements. Then the wave forces and the moment on the device is numerically investigated. The model and experimental results indicate that the horizontal wave force on the front barrier wall is much larger than that on the internal barrier wall. The joint between the back wall and the ground withstands the largest bending moment, therefore, is most vulnerable to structure damage and fatigue.
Preliminary Experimental Study on the Influence of the Local Wind Field on Forces From Breaking Waves on a Circular Cylinder
Authors: Caroee Kristoffersen Julie , Bredmose Henrik , Georgakis Christos Thomas , Tao Longbin 
Published: November 2019

Abstract
The spatial localized influence of wind on wave induced load on a flexible cylinder has been assessed throughout a test series conducted in a wave-wind-current flume at Newcastle University. The tests are motivated from other experimental and numerical investigations showing air flow separation on the leeward side of steep waves that can lead to added wind energy transfer, which could suggest an increase in the impulsive wave loading. The waves are generated as focused waves, resulting in a plunging breaker, leading to an impulsive wave load. The test model was equipped with a load cell measuring the connection load. Due to the flexibility of the cylinder, the measured force response shows oscillations and dynamic amplification of the load. The maxima of the force responses are compared for the tests with and without wind. Another measure for comparison is the local and short-lived impulse, which is responsible for the amplification. This impulsive load is estimated from the load cell and acceleration measurements. For the tests in this study, the introduction of wind over the breaking waves does for some cases lead to a slight increase in the peak of the impulsive load and thereby the load response, although large scattering is present. Further investigations are needed to verify this effect. Some differences in the time series of the free surface elevation are observed when wind is present, but the maximum of the surface elevation does not change notably, and the slope is only minimally changed, meaning that this should not give basis for the differences in the loads.
Laminar Displacement Flows in Vertical Eccentric Annuli: Experiments and Simulations
Authors: Etrati Ali , Frigaard Ian 
Published: November 2019

Abstract
We present a numerical investigation of laminar miscible displacement flows in narrow, vertical, eccentric annuli. This study is motivated by the primary cementing stage of oil and gas well production, where successful displacement of drilling mud is crucial for the well integrity and zonal isolation. The large number of characterizing parameters makes a complete description of such flows challenging. In turn, this means that the design of effective strategies for primary cementing is a difficult task. As a result the existing literature is mostly based on non-inertial Hele-Shaw models and experiments in narrow annuli, where the dimensionality of the problem is reduced. In this preliminary study, we run a series of three-dimensional numerical simulations, using a Volume of Fluid (VOF) method to capture the interface between the fluids. Both Newtonian and non-Newtonian fluids are considered, and a variety of different phenomena are observed, e.g. dispersive spikes, static layers, instabilities and secondary flows. The range of flow parameters used in the simulations are similar to existing experimental data to allow for a preliminary comparison. The results show qualitative agreement with the experiments and gap-averaged models.
Solitary Wave Interaction With Vertical Porous Barriers
Authors: Francis Vivek , Ramakrishnan Balaji , Rudman Murray 
Published: November 2019

Abstract
Tsunami waves pose a threat to the coastal zone and numerous studies have been carried out in the past to understand them. The present study — carried out in the 2D wave flume at the Ocean Engineering Laboratory of IIT Bombay — focusses on the interaction and run-up of solitary waves on coastal protection structures in the form of thin, rigid vertical porous barriers with special attention given to the degree of energy dissipation. In order to understand the physics of the energy dissipation problem, the propagation of the solitary wave and its interaction with the porous barrier has been studied from the viewpoint of energy balance. Based on this, a proper relationship for the wave energy dissipated by the barrier has been developed. Using this relationship, the experimental data has been analyzed and we have determined that the plate porosity that gives the optimal energy dissipation characteristics lies within the 10–20% range. In addition, using the experimental data, we have derived a formula for calculating the maximum wave run-up on the porous barrier models which should be useful in the planning, design, construction and maintenance of coastal protection structures.
The Wave Energy Converter Control Competition: Overview
Authors: Ringwood John , Ferri Francesco , Tom Nathan , Ruehl Kelley , Faedo Nicols , Bacelli Giorgio , Yu Yi-Hsiang , Coe Ryan G. 
Published: November 2019

Abstract
Over the past two years, a wave energy converter control systems competition (WECCCOMP) has been in progress, with the objective of comparing different wave energy converter (WEC) control paradigms on a standard benchmark problem. The target system is a point absorber, corresponding to a single float with an absolute reference, of the WaveStar WEC prototype. The system was modelled in WEC-Sim, with the hydrodynamic parameters validated against tank test data. Competitors were asked to design and implement a WEC control system for this model, with performance evaluated across six sea states. The evaluation criteria included a weighted combination of average converted power, peak/average power, and the degree to which the system physical constraints were exploited or temporarily exceeded.
This paper provides an overview of the competition, which includes a comparative evaluation of the entries and their performance on the simulation model. It is intended that this paper will act as an anchor presentation in a special session on WECCCOMP at OMAE 2019, with other papers in the special session contributed by the competitors, describing in detail the control algorithms and the results achieved over the various sea states.
Low-Cycle-Fatigue Crack Closure Effect of Ship Cracked Plate Considering the Accumulative Plastic Damage
Authors: Song Yuelin , Yang Ping , Peng Ziya , Jiang Wei , Hu Kang 
Published: November 2019

Abstract
In this paper, the relationship between crack closure level and the crack length is studied with experiment and numerical simulation under different low cycle fatigue (LCF) loads. The evolution mechanism of crack closure behavior is explored through the variations of the accumulative plastic strain and compressive stress near the crack-tip. The compressive residual stress is separated into two parts for comparative analysis, namely: the stress field ahead of the crack tip and the stress field of the wake region. The magnitude of the compressive stress field is obtained by the integration along the crack propagation direction of the normal stress. The results show that there is an excellent correlation between LCF crack closure level and the magnitude of the compressive stress in the plastic wake, which provides a new way to further study the complex mechanism of crack closure under LCF loads.
CFD-Based Study of a Tidal Current Turbine in a Horizontal Axis Under Regular Waves
Authors: Liu Jing , Xiao Longfei , Jing Fengmei 
Published: November 2019

Abstract
The horizontal-axis tidal current turbine is often installed in near-surface to use the high flow velocity of tidal current, and many designers have found the effect of wave on the hydrodynamic performance of tidal current turbine. The present study focuses on the hydrodynamic analysis of a tidal current turbine in a horizontal axis under the condition of regular waves, based on CFD method. The experimental data are used to verify the feasibility of the method. A non-dimensional parameter k is defined as the ratio of tip submergence to wave amplitude. It is shown that the numerical method is good to predict the hydrodynamic performance of horizontal axis turbine. By comparing the power coefficient and axial load coefficient in different tip submergence and wave amplitude, the effects of tip submergence and wave amplitude on the hydrodynamic performance of tidal current turbine are analyzed.
Coastal Engineering Analysis, Field Measurements, Numerical Modeling and Design for the Optimized Extension of the Beach in Ras Al-Ardh Area, Salmiya, Kuwait
Authors: Neelamani S. , Shuhaibar Bassam N. , Al-Salem Khaled , Al-Osairi Yousef , Karam Qusaie E. , Al-Houti Dana , Al-Anjari Noor 
Published: November 2019

Abstract
Maintaining and retaining a quality sandy beach is a primary requirement for attracting people and tourists in any coastal country. Tourism Enterprises Company (TEC) in Kuwait owns 230 m long sandy beach in Ras Al-Ardh Sea Club, Salmiya, Kuwait. The beach has been eroding because of strong hydrodynamics forces from waves and currents. TEC wants to develop a stable sandy beach of 30 m wide. Kuwait Institute for Scientific Research (KISR), Kuwait is assigned to carry out the required scientific studies. In order to make sure a stable quality beach will exist, KISR has carried out the needed studies, which involves the field measurements such as bbathymetry survey, current and tidal variations, physical characteristics of beach soil, beach and sea bed profile, establishing the design parameters such as waves, currents, tide and wind. Hydrodynamic model study using DELFT3D model for the present and for the proposed extended groin conditions with beach nourishment were carried out. Also numerical modeling using GENESIS model to understand the future shore line changes due to the proposed development was carried out. Design of Groins to estimate the weight of armor units and weight of inner layers were carried out. The particle size and quantity of sand needed for reclamation of 30 m wide beach was estimated. Based on the study, it is recommended that the sandy soil to be used for 30 m wide beach nourishment should have D50 greater than 0.42 mm (say 0.5 mm) and D10 greater than 0.25 mm. The borrow pit much be selected by keeping this soil characters in mind. It is recommended to use a submerged offshore breakwater in order to retain the beach sand in place and for reducing the maintenance nourishment. Otherwise, large quantity of the capital nourished beach sand will escape into the deeper water due to strong current coupled with waves and steep seabed slopes. Environmental Impact Study was carried out as per Kuwait Environment Public Authority requirements to bring out the impacts due to beach filling and the construction submerged offshore barrier and extension of east groin for a distance of 30 m. TEC will implement the recommendations for developing the beach in Ras Al-Ardh sea club and will be useful to attract more people to use this beach.
Unsteady Numerical Simulation of the Behavior of a Ship Moving in Head Sea
Authors: Lungu Adrian 
Published: November 2019

Abstract
The paper follows a previous work of the author that dealt with ship resistance and self-propulsion numerical investigations, proposing a series of numerical simulations performed to assess the seakeeping performances of the KCS model which moves in regular head waves. Various simulations of the free-surface flow around the hull equipped with rudder moving either in calm water or in heading waves are proposed. For the calm water case, in which a series of six Fr numbers is considered, verification and validation based on the grid convergence tests are performed. Then, a series of five different simulations for various incoming wave characteristics are presented and discussed in every detail. Comparisons with the experimental data [1], [2] are provided aimed at validating the numerical approaches in terms of the total resistance coefficients as well as the heave and pitch motions characteristics. Several remarks will conclude the findings of the present work.
Parametric Resonance Analysis of a Submerged Floating Pipeline Considering Uncertainties
Authors: Yang Hezhen , Xiao Fei 
Published: November 2019

Abstract
The submerged floating pipeline is floating at a certain ocean depth with tethers anchored to the seabed. This novel concept of pipeline can be a promising solution for challenging seabed conditions. Because the pipeline is floating at the mid-deep water and does not interact directly with the seabed, there is no need to do any seabed intervention work and wave forces on the pipeline can also be ignored. But the dynamic response of this type of pipeline under strong currents poses several challenges for design of floating pipeline. This work investigates the parametric resonance of submerged floating pipeline between two floating structures. The parametric resonance can lead to the huge motions and fatigue damage of the pipeline. Thus, it is essential to investigate the parametric resonance of the submerged floating pipeline system under combined parametric and vortex excitations considering uncertainties. Hill’s equation of dynamic responses of the pipeline are derived and hill stability diagrams are used to analyses the corresponding motion stability. The effect of the significant uncertain factors on the probability of the parametric stability is investigated using the metamodel method. According to analyses, some effective measures are given to the designers to avoid the parametric instability for the submerged floating pipeline design.
Improved Design of Next Generation Hull-Platform “noah-FPSO Hull”
Authors: Tanaka Shigeru , Sogawa Yasuhiro 
Published: November 2019

Abstract
The achievement of low cost and fast-track construction for new-build FPSO hulls are challenging problems. In order to solve these problems, the authors developed and reported unique modular design and multi-yard construction concept, “noah-FPSO Hull” [1][2][3]. Since then, the authors continued to improve its design and expanded its flexibility for harsh environment and customer’s requests. As a result, new standardized fore/aft modules and cargo tank module have been developed to expand the flexibility.
This paper presents the design of the newly developed modules and the feasibility for harsh environment.
Improvement of Wave Loads Estimation From Spatial Pressure Distribution on Ship Hull
Authors: Waskito Kurniawan T. , Kashiwagi Masashi 
Published: November 2019

Abstract
In modern shipbuilding industry, merchant ships tend to increase in size. Accurate prediction of the vertical bending moment in large-maplitude waves has become important for structural design. For establishment of an accurate estimation method, more detailed local hydrodynamic quantities such as the spatial pressure distribution on the whole ship hull surface should be checked. For that purpose, the experiment has been conducted by means of Fiber Bragg Grating (FBG) sensing technology. Using the measured local pressure distribution by only sticking the FBG pressure sensors onto the hull surface, we can evaluate the wave loads; which may lead to establishment of a new evaluation method for the wave loads without using a segmented model. We confirm favorable agreement of the pressure distribution between measurement and computation by Rankine Panel Method (RPM). Furthermore, the vertical bending moment computed at some transverse sections shows favorable agreement between measured and computed results.
Correlation Between Steel Microstructural Characteristics and the Initiation and Arrest Toughness Determined From Small-Scale Mechanical Testing
Authors: Taylor Jessica , Moore Philippa , Mehmanparast Ali , Kulka Rob 
Published: November 2019

Abstract
Modern high Charpy toughness steels can nonetheless show low crack arrest toughness[1]. In this paper, the relationship between initiation and arrest toughness is investigated in five different carbon steels, including S355 structural steels, X65 pipeline steel, and high strength reactor pressure vessel, RPV, steels. The results from small-scale mechanical tests, including instrumented Charpy, drop weight Pellini, fracture toughness, and tensile testing (including STRA in the through-thickness direction) were used to determine the behaviour of the different steels in terms of initiation fracture toughness and crack arrest toughness parameters. There was no correlation between the upper shelf initiation toughness and the arrest toughness when the results from the five steels were collated. The mechanical test results were then correlated to the steels’ microstructural characteristics, including parent metal microstructure, average grain size and grain aspect ratio to identify the relative roles of microstructure and texture in the fracture initiation and arrest performance of carbon steels.
Software Simulation and Experimental Study on Wax Deposition Pattern of Deep Condensate Gas
Authors: Wang Jie , Zhou Fujian , Yao Erdong , Fan Fan , Yuan Lishan , Xue Yanpeng 
Published: November 2019

Abstract
The Bozi block of Tarim Oilfield is a typical tight sand condensate gas reservoir with serious wax plugging issue. It is necessary to study the phase behavior and the wax deposition pattern of well fluids in Bozi gas reservoir, which provides the phase enveloping diagram of the condensate gas and can help to control the paraffin deposition. In this study, the PVT tester and self-designed microscopic solid deposition tester are used to get the phase enveloping curve of the condensate gas, which is combined with software simulation results and production data of Bozi 104 well to analyze wax deposition from formation to wellbore, wellbore to ground and surface pipeline. The main conclusions and suggestions are as follows: with different temperature and pressure, condensate gas produces different phase regions such as gas phase, gas-liquid phase, gas-solid phase, gas-liquid-solid phase, etc. Above the dew point pressure, the WAT is less impacted from pressure while the WAT gradually decreases due to the dissolution effect below the dew point pressure. The experimental results are used to revise the software simulation results and then to obtain the phases of different temperature and pressure regions. The state envelope is used to predict the liquid separation and wax production situation at different production stages; the liquid condensation and waxing area of the Bozi 104 well lies in the surface pipeline behind the nozzle, where appropriate wax prevention measures are needed.