bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computer Simulation of Laboratory Experiments With Two-Phase Slug Flow Induced Oscillations on a Submerged Flexible Catenary Pipe
Authors: Cesar de Oliveira Trigo Caio , Kazuyuki Morooka Celso , Nascimento Bordalo Sergio , Yamamoto Marcio 
Published: August 2024

Abstract
Experiments were conducted for the oscillations of a submersed suspended flexible pipe ex]cited by the internal two-phase slug flow of liquid and gas. Computer simulations were carried out with proprietary numerical tools to evaluate suitable modeling methods for pipe oscillations. The experiment was conducted with a pipe set in a catenary configuration inside a two meters deep water tank. Water and air were injected into the pipe at its bottom end with various flow rate combinations, forming horizontal slug flow patterns. The slug two-phase flow generated intermittent loads on the pipe promoting its oscillation. At the same time, cameras monitored the dynamic response of the pipe. Processing the video images frames generated time-history records of the movement of the pipe. In this paper, computer simulations were performed to determine the frequencies and amplitudes of the pipe oscillations, which were compared to those from the experiment. A proper scaling up of experimental results with the support of computer simulations should be helpful for the analysis and design of suspended risers employed in offshore petroleum platforms carrying up oil and gas from petroleum reservoir wells to floating production facilities.
A Numerical Investigation on Collapse Modes of Stiffened Plates Under Combined Dynamic Loads
Authors: Guo Guangyu , Cui Jinju , Wang Deyu 
Published: August 2024

Abstract
In actual navigation environments, hull structures are subjected to multiple combined loads, in many cases, such as hogging and slamming, transient and impactive load components occur frequently. Accordingly, the collapse behavior and ultimate strength of ship structures under combined dynamic load cases have received considerable interest. As the basic member of ship structures, stiffened plates contribute to the loading capacity and the ultimate strength of the hull structure. Thus, it is necessary to further investigate the mechanical properties and ultimate strengths of stiffened plates subjected to combined dynamic loads, including lateral pressure, longitudinal load and transversal compression. In this study, a series of numerical models of stiffened plates are designed according to recommendations of ISSC. Then, with the help of nonlinear finite element method (NFEM), the structural responses and deformation behaviors of stiffened plates subjected to combined dynamic in-plane and out-of-plane loads are simulated. With the help of NFEM, the collapse modes of the stiffened plates under combined dynamic loading cases are researched, and a further explanation of the structural response of stiffened plates under combined dynamic load cases is derived.
Manoeuvring Modelling and Control Design of Autonomous Vessels on Inland Waterways
Authors: Zhang Chengqian , Dhyani Abhishek , Ringsberg Jonas W. , Thies Fabian , Reppa Vasso , Negenborn Rudy R. 
Published: August 2024

Abstract
Autonomous inland shipping has great potential to enable intelligent and sustainable freight transport. At the same time, with the increasing traffic on confined waterways, ensuring safe operations of these autonomous inland vessels within limited operational spaces becomes imperative. This will require considering hydrodynamic effects during control design stages. This study presents a comprehensive analysis of an autonomous inland vessel’s manoeuvrability and controller design. The ship’s motions are modelled using an enhanced Manoeuvring Modelling Group (MMG) model to account for the hydrodynamic effects of inland waterways, including water depths, river currents, and bank effects. A verification study is conducted utilising a pusher-barge prototype model in shallow water to verify the model’s accuracy. Through the implementation of a controller, a course-keeping study is conducted to assess the vessel’s steering performance across various inland waterway scenarios, including sailing along river bends and waterway intersections. The results show that the manoeuvring model can generate fast and accurate vessel trajectory predictions. It is found that the proposed control technique proves effective in mitigating the confinement effects and countering disturbances caused by river currents, thereby ensuring efficient course-keeping suitable for the considered type of autonomous vessels on inland waterways.
Impact Loads on Ships From Breaking Waves
Authors: Rognebakke Olav , Ruth Eivind , Landet Tormod , Austefjord Håvard 
Published: August 2024

Abstract
Plunging breaking waves may cause large impact loads on ships. Neither the risk of such impacts nor the magnitude of the resulting loads is much studied or well understood. Breaking waves in open sea typically occur in steep non-stationary growing sea-states. Recent advances in modelling of highly nonlinear wave conditions combined with computational fluid dynamics provide a means to quantify the frequency of breaking wave events. A higher-order spectral wave model is used to initialize large-domain wave propagation analyses in OpenFOAM. Breaking wave events are identified, and the risk of hitting different part of a vessel’s hull is evaluated. This includes evaluation of relative motions between the ship and breaking wave profile. Calculating linear vessel motions using a linearized wave field provides a good approximation compared to including the vessel in the CFD calculations. The focus is on beam-sea waves impacting the side of the ship. Existing rules and design practice account for dynamic wave loads but not large impulsive loading outside of the area vulnerable to bow-or stern slamming loads. A calculation framework is established that can be used to quantify how the risk of excessive loads depends on sea-state characteristics and vessel operation. General observations are made about the risk for high impact loads from breaking waves, and mitigating actions are discussed.
On the Design, Hydrodynamic Modelling and Response Analysis of a New Concept FOWT Platform
Authors: Islam Touhidul , Venugopal Vengatesan 
Published: August 2024

Abstract
This paper primarily focused on the design and hydrodynamic analysis of a new concept Floating Offshore Wind Turbine (FOWT) with a capacity of 5 MW or above. The proposed concept has smaller dimensions, hence reduced material and displacement. The platform consisted of large volume cylindrical structures at its base and near the waterplane, and, this was done to increase the distance between the FOWT’s centre of gravity and buoyancy. Furthermore, the base cylinders work as containers for ballast and effectively reducing vertical motion.
For a detailed hydrostatic stability analysis, general hydrostatics (GHS) software was used to verify different loading conditions. During the stability analysis, it was found that the platform could be designed with relatively lower displacement to comply with the static stability, however, when subjected to wave loads, it exhibited reduced stability with significant motion amplitudes. Nonetheless, the sizing of the platform was primarily determined by the hydrodynamic heave and pitch natural periods, considering them to be outside the wave period range.
Once the preliminary dimensions were chosen, the radiation-diffraction tool BV Hydrostar was used to estimate hydrodynamic coefficients, transfer functions and for detailed hydrodynamic modelling and analysis of the platform. Viscous loads from the slender elements were accounted using the drag term of Morison’s equation for platform motion.
The turbine tower was modelled according to the description found in literature. Rotor-nacelle assembly was modelled as a point mass. The resulting platform has a 30% reduction in displacement and save at least 15% of material weight compared to the NREL DeepC platform. Motion RAOs for the platform in heave, roll, and pitch show peak values near natural periods, however, values were comparable to the NREL DeepC platform.
Vortex Induced Vibrations of a Lazy Wave Dynamic Power Cable Under Various Currents and Propagation Directions: Analysis of Strain
Authors: Moideen Rameeza , Venugopal Vengatesan , Chaplin John 
Published: August 2024

Abstract
Vortex induced vibrations (VIV) of a flexible dynamic power cable in lazy wave configurations were investigated experimentally to understand their behaviour under currents of various magnitudes. The preliminary study investigates the effect of increasing current magnitudes in the range 0.1–0.8 m/s and for three different current propagation directions (i.e. 0, 90 and 180 degrees relative to the cable’s alignment) on a model power cable of external diameter 0.031 m, 5m long. The experiments were undertaken at the FloWave combined wave-current facility of The University of Edinburgh. They fall in the subcritical range with Reynolds numbers from 103 to 104. The cable was instrumented with water-proofed strain gauges at seven locations along the its length at 0.5 m intervals to measure total bending strain at each point. The cable was also instrumented with six-component load cells while an optical system measured displacements at a large number of locations. However, these are not presented in this paper.
This paper reports bending strains and the corresponding response spectra at seven locations along the length of the cable. The impact of VIV on measured strains and their effect on response frequencies (hence the Strouhal number) are illustrated over a range of current magnitudes and directions. A detailed analysis of the data collected, results and discussions are presented in the paper.
Characterization of Dynamic Pore-Throat Structure and Petrophysical Properties in an Unconsolidated Sandstone Reservoir
Authors: Ge Lizhen , Liu Guangfeng , Luo Zhoujun , Chen Xiaoming , Ma Teng , Yang Daoyong 
Published: August 2024

Abstract
In this study, a comprehensive and practical technique was developed to study the dynamic changes of pore-throat structure and petrophysical properties of unconsolidated sandstone reservoirs during long-term water injection. Experimentally, core samples were gathered from unconsolidated sandstone reservoirs for thin-section preparation and analyzed using laser particle size and X-ray diffraction techniques. In addition to identifying and classifying pore types and clay minerals, the size, fraction, and distribution of particles were also determined and categorized. Furthermore, a high-pressure mercury injection test was conducted on the core after waterflooding so as to quantify alterations in the microscopic pore-throat structure. The dispersion of clay minerals breaks the formation bond, leading to the fall and migration of clay and fine silt, and the content of clay and fine silt decreases, resulting in the change of pore-throat structure. Compared with the change of pores, the change of throat has a greater influence on the seepage behaviour, but such a change mainly occurs in the early stage of waterflooding. The fractal dimension of the pore-throat structures increases from 2.51 to 2.58, enhancing the heterogeneity and making the seepage channels more concentrated. The pore-throat structure was changed by 90% when water was injected to 200 PVs, gradually changed until 300 PVs of injected water, and then remained basically unchanged afterwards.
Consequence Analysis of a Bunkering Facility for Liquid Hydrogen Loading and Unloading
Authors: Schiaroli Alice , Campari Alessandro , Paltrinieri Nicola , Cozzani Valerio , Ustolin Federico 
Published: August 2024

Abstract
Hydrogen is widely regarded as a key option for the replacement of fossil fuels in the near future. Despite compression being the most well-known and widespread technology for hydrogen storage and transportation, liquid hydrogen (LH2) is preferable for large-scale applications where a greater energy density is crucial to reach the desired storage capacities. For instance, in 2020–2021, the HySTRA (Hydrogen Energy Supply-chain Technology Research Association) pilot project was carried out to demonstrate the feasibility of a large-scale liquefied hydrogen energy supply chain from the production site in Australia to the receiving terminal in Japan. The unloading facility, which includes a 2,500 m3 LH2 spherical storage tank, a boil-off tank, and other equipment for the transfer of LH2 from land-based facilities to the LH2 truck trailers, is located in the Port of Kobe, in the northeast section of Kobe Airport Island. This facility is the world’s first liquefied hydrogen receiving terminal for unloading of a LH2 marine carrier. Given the hazards related to hydrogen storage and handling that derive from its high flammability, safety plays a fundamental role in hydrogen applications, particularly when managing large amounts of fuel. In the present study, a risk analysis is performed to estimate the risk related to a liquid hydrogen bunkering facility. First, the most safety-critical components are identified through a preliminary risk analysis. Second, more detailed modelling is carried out to quantify the consequences of an unexpected loss of containment (LOC) from the most critical piece of equipment. The consequences are expressed in terms of separation distances and calculated by integral models from the effects of possible final events (e.g., fires and explosions).
Low Frequency Energy in Measured Waves in a Narrow Norwegian Fjord
Authors: Jena Parthasarathi , Li Lin , Haver Sverre , Xiang Xu 
Published: August 2024

Abstract
The E39 Coastal Highway Route project undertaken by Norwegian Public Roads Administration aims at replacing existing ferry crossings by constructing permanent road connections using bridges along the western coast of Norway. One of the bridge designs being developed is a beam bridge resting on floating pontoons. In contrast to conventional bridges, a floating bridge rests on pontoons floating on the water surface and are affected to a much greater extent by waves and currents in the waters it spans. In order to have a solid basis for taking the environmental loads into account in the bridge design a wave measurement campaign was initiated at the bridge fabrication location.
The wave measurement was carried out using a small diameter wave buoy with a proven track record in the offshore industry. The location of the wave measurement campaign is a narrow fjord surrounded by relatively high terrain. The fjord, being sheltered from swells from the North Sea and considering the available fetch length, it was expected that the measured waves would consist of purely wind generated waves with peak wave period, Tp, between 2s to 7s. However, the observed wave signal showed spurious long period waves with Tp in the range of 20s to 30s interspersed seemingly at random throughout the measured data. This paper discusses possible reasons for the observed low frequency energy. Harbor resonance in the fjord, resonance in the mooring system of the buoy, and passing ship interaction with the buoy were investigated as possible reasons for the presence of the low frequency energy. A method for identifying the low frequency energy and filtering them out using wavelet analysis of buoy heave signal is proposed.
Performance Assessment of Safety Barriers in Liquid Hydrogen Bunkering Operations Using Bayesian Network
Authors: Tamburini Federica , Ustolin Federico , Cozzani Valerio , Paltrinieri Nicola 
Published: August 2024

Abstract
Liquid hydrogen (LH2) has gathered interest as an eco-friendly energy carrier for marine transportation, avoiding carbon emissions and supporting sustainable shipping. However, LH2 intrinsic flammable characteristics pose safety concerns towards people and assets. Ensuring the effectiveness of safety barriers is paramount in preventing accidents and mitigating risks associated with LH2 bunkering operations. In this regard, among several quantitative performance assessment methods, Bayesian Networks (BNs) gained momentum, offering a statistical approach able to account for multifaceted safety factors. This paper evaluates safety barriers’ performance by translating Event Tree-Fault Tree diagrams into BNs. BNs incorporate root nodes representing basic events leading to the failure of the safety barriers, assigning failure probabilities from technical literature and Human Reliability Analysis approaches. Conditional Probability Tables quantify dependencies, mapping safety barrier interconnections. A case study on ship-to-ship bunkering affected by a LH2 release is considered to illustrate the application of BNs in the context of safety barriers performance assessment. Findings highlight BNs’ utility in assessing safety barrier performance, providing a tool for regulatory agencies, industry stakeholders, and safety experts to inform LH2 bunkering best practices. This aligns with advancing environmentally responsible LH2 maritime transportation while enhancing safety measures.
Distributions and Impact Factors of Organic Carbon in the Coastal Areas of Yangtze River Estuary in the Summer of 2023
Authors: Yang Zhongyuan , Lou Sha , Chen Shizhe 
Published: August 2024

Abstract
Since the start of the industrial revolution, global average temperature has been increasing year by year due to the rapid increase in atmospheric carbon concentrations. Estuarine carbon cycle processes are hotpots of greenhouse gas (CHG) emissions and play multiple roles in the global carbon budget. The driving factors of organic carbon in coastal wetlands are crucial for understanding the process of estuarine carbon cycle. However, the relationship between organic carbon and surrounding environmental factors is complex, and the impact pathways of controlling factors on organic carbon remain unexplored. Therefore, this study employed field sampling and statistical techniques to study the relationships between organic carbon and primary influencing factors in seven coastal wetlands along the Yangtze River Estuary during the summer (June-August 2023). Results showed that the average of organic carbon concentration in August was higher than that in June and July. The organic carbon concentrations in Sanchagang (SCG) and Dazhihe (DZH) were higher than those in other sampling points. Salinity, total dissolved solids, electrical conductivity and resistivity had significant impacts on organic carbon. Partial least squares path modeling indicated that the effect of salinity regulation and biogeochemical environment on organic carbon is a direct and dominant pathway (path coefficient ⩾ 0.45). Hydrodynamics had the greatest indirect effect on organic carbon but the total effect of hydrodynamics was insignificant. This work offers an insightful lens for better understanding organic carbon processes in coastal wetlands. It provides a theoretical basis for better assessing blue carbon storage in the context of global change.
Vortex-Induced Vibration of Two Rigidly Coupled Cylinders in Tandem Arrangement With Low Mass Ratios
Authors: Yu Zhipeng , Wang Enhao , Wu Hao , Xu Hongteng , Gao Chenxi 
Published: August 2024

Abstract
Vortex-induced vibration (VIV) of two rigidly coupled cylinders in tandem arrangement with a fixed center-to-center separation of 2 (s/D = 2) is numerically investigated in a laminar flow with Re = 150. Results are examined over a domain of reduced velocities ranging from 0.25 to 100 and very low mass ratios are considered, i.e., m* = 0.02, 0.1, 0.3 and 0.9, respectively. It is found that the amplitude at the infinite reduced velocity increases smoothly as the mass ratio decreases, whereas the amplitude experiences a sharp increase for an isolated vibrating cylinder below the critical mass ratio at the same Reynolds number. Interestingly, unlike the VIV of an isolated cylinder, the time traces of the displacement is quasi-periodic in the first part of the low branch for the two-cylinder system. This so called beating phenomenon is identified as a consequence of the different flow state, particularly the presence or absence of an active gap flow. The present study highlights significant distinctions in the amplitude response associated with wake patterns between the VIV of the two-cylinder system and that of the isolated cylinder.
Hydrodynamic Force of an Obliquely Oscillating Cylinder in Steady Flow
Authors: Ren Chengjiao , Cheng Liang , Tong Feifei 
Published: August 2024

Abstract
This study conducts a series of three-dimensional numerical simulations to explore the dynamics of an oscillating cylinder in steady current. Simulations are set at a fixed Reynolds number of 500 for the steady current and a small oscillation amplitude of 0.4 cylinder diameter. Seven oscillation angles θ from 0° to 90°, defining as the orientation of the cylinder oscillation relative to the current, have been investigated across various oscillation wavelengths λ*. The impact of θ on the wake characteristics can be broadly categorized into three regions. For small λ* (less than 1.5), the flow is predominantly influenced by the cylinder oscillation, with forces that vary monotonically with respect to θ. In contrast, at larger λ* (greater than 10), cylinder oscillation becomes negligible, and the wake is primarily driven by the incoming flow. Complex wake interactions exist at intermediate λ* = 1.5–10, particularly in terms of the occurrence of lock-on states. The primary lock-on at θ = 90° (period-1 wake), characterized by a repeatable vortex shedding pattern over each oscillation period, develops at all angles. Meanwhile, the primarily lock-on state at θ = 0° (period-2 wake) is only observed for θ up to about 75°. As θ increases from 0°, both lock-on states shift towards smaller λ*.
Comparison of Two Types of Wave Buoys: Linear and Second-Order Motion
Authors: Ding Yue , Taylor Paul H. , Hlophe Thobani , Zhao Wenhua 
Published: August 2024

Abstract
Wave data from oceanographic buoys remains indispensable in offshore and coastal engineering. Modern wave buoys can produce semi-Lagrangian time histories of motion in three dimensions (one vertical and two horizontal) in addition to the standard statistical output. A recent study (Ding et al., 2023) reveals that, while the three translational motions of a wave buoy are dominated by the linear components, there is significant nonlinearity in the horizontal plane. This study uses field data from the Southern Ocean off Albany, Western Australia, measured from four closely spaced buoys: three Sofar Spotters and a Datawell Directional Waverider-4. The measured time histories measured by the different types of wave buoys in three orthogonal directions and the relationship between them have been systematically investigated, for the first time. Significant second-order components in both vertical and horizontal directions are observed.