bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrodynamic Forces Acting on Small-Diameter Pipelines Under Combined Irregular Wave and Current Flows: A Case Study
Authors: Teng Yunfei , Chen Zhanjie , Griffiths Terry , An Hongwei , Draper Scott , Mohr Henning , Cheng Xin , Hu Xiaoyuan , Cheng Liang 
Published: September 2023

Abstract
The hydrodynamic forces induced by combined irregular waves and currents acting on a small-diameter pipeline are investigated based on some physical tests. The results suggest that the Morison equation leads to poor predictions of the time-variant forces when the pipeline is mounted on the bottom. For the on-bottom cases, the method suggested by Jacobsen et al. (1988) is demonstrated to work better than the traditional Morison equation. However, the Morison equation performs reasonably well on describing the temporal forces when the pipeline is far away from the seabed.
Wave-Induced Loading Simulation for a Semi-Submersible FOWT Platform Using CFD-SWENSE Coupled Solver
Authors: Shen Cong , Chen Nian-Zhong 
Published: September 2023

Abstract
The low-frequency wave-induced loading on semi-submersible floating wind turbines is normally small, but the loading can result in large motions due to resonant responses in surge and pitch. Therefore, one of the most important concerns regarding the numerical simulation of wave-induced loading on floating wind turbines is how to accurately predict the difference-frequency wave-induced loading, especially near the resonance frequencies. The potential flow method based on the Morrison formula cannot consider the fluid viscosity, and thus the numerical accuracy of the prediction of wave-induced loading is generally insufficient, and usually underestimating the highly nonlinear difference-frequency wave loading. Navier-stokes equation based the computational fluid dynamics (CFD) method has shown the merit for improving the numerical prediction of nonlinear wave-induced loading and motions of offshore floating structures, however, the computational cost of the CFD method is too expensive as a higher-fidelity modeling tool, which is not suitable for engineering application at the current stage. This paper aims to establish a CFD-SWENSE (Spectral Wave Explicit Navier-Stokes Equations) coupled solver to solve this problem but maintaining sufficient numerical accuracy. The potential part (the incident waves) is solved with the spectral wave model. The viscous part (the complementary perturbation on the incident waves) is solved with the CFD solver. Based on this potential viscous flow coupled solver, the differential frequency of wave loading of a semi-submersible floating body under the influence of bichromatic waves is investigated. The results show that the computational efficiency of the coupled solver is improved compared with the CFD method, however, the wave-induced loading predicted by the coupled solver is in good agreement with that predicted by the CFD method.
Validation of CFD-Based Numerical Wave Basin for a Floating Offshore Wind Turbine in Irregular Waves and Dynamic Wind
Authors: Jang Hyunchul , Jang Hakun , Teng YihJeng 
Published: September 2023

Abstract
Several recent benchmark studies have demonstrated that Computational Fluid Dynamics (CFD) is capable of capturing both nonlinear and viscous effects in marine hydrodynamics and predicts wave- and current-induced offshore platform motions accurately. A CFD-based numerical wave basin developed by Technip Energies, MrNWB [1, 2], has been well-validated against physical model test results for various offshore floating platforms including a floating offshore wind turbine in National Renewable Energy Lab (NREL)’s OC6 CFD JIP [3]. However, the OC6 CFD JIP focused on the motion responses corresponding to hydrodynamic loadings only.
In the present study, a new coupled analysis methodology is introduced to accurately predict the motion responses of a floating offshore wind turbine considering wind turbine. In the present coupled analysis, aero-servo-elastic behaviors of the wind turbine blade and tower are simulated by OpenFAST [4], and the hydrodynamic loads on the floating platform and mooring system are simulated by Technip Energies’ CFD-based numerical wave basin tool, MrNWB. For the fully coupled aero-hydro-servo-elastic simulation, the OpenFAST dynamic solver calculates the system responses of floating offshore wind turbine, and the hydrodynamic loads on the floating substructure are integrated into the CFD solver with respect to the 6-DOF platform motions. This new coupled analysis tool is called Wind Turbine Numerical Wave Basin (WTNWB).
This paper presents validation of WTNWB for the DeepCWind semisubmersible model tests in irregular waves and a steady wind condition. The validation results are systematically compared with model test results [5, 6] and show good agreement.
Experimental Evaluation of Supercritical CO2 Enhanced Oil Recovery and Storage Capacity Using Dual-Core Core Flooding Technology for Carbonate Reservoirs
Authors: Zhou Xianmin , Yu Wei , Kamal Muhammad Shahzad , Wu Yu-Shu , Khan Sarmad Zafar , Al-Abdrabalnabi Ridha 
Published: September 2023

Abstract
The depleted oil reservoirs are considered as the potential geological storage site for CO2, which is one of the solutions to carbon emissions and the increased temperature in the atmosphere. The geological properties of the depleted oil reservoir, such as reservoir heterogeneity, directly affect the amount of CO2 storage. Unfortunately, no research has been done on this topic. In this study, we experimentally studied the effect of reservoir heterogeneity on oil recovery factors in cases of seawater flooding and supercritical CO2 (sc-CO2) miscible injection and the resultant sc-CO2 storage in depleted oil reservoirs at the end of the oil field development.
A dual-core flooding experiment involving two reservoir carbonate core samples with different permeabilities and porosities was carried out using live oil, which is that gas dissolves in the crude oil as the displaced phase. Seawater and sc-CO2 as the displacing phases were used to conduct water flooding and the miscible injection process under reservoir conditions (overburden pressure of 4,500 psi, pore pressure of 3,200 psi, and reservoir temperature of 102°C), respectively. The scCO2 miscible injection process was followed by seawater flooding to recover the remaining oil after seawater flooding and evaluate the storage capacity of sc-CO2.
From the results of this study, it was found that sc-CO2 miscible injection following seawater flooding can recover additional oil, which is related to the properties of rocks. We also found that high-permeable rock has a significant potential for scCO2 storage compared to low-permeable rocks. In addition, the effect of reservoir heterogeneity on the injectivity of sc-CO2, permeability loss, and scCO2 storage efficiency is-also discussed.
Autonomous Port Navigation With Ranging Sensors Using Model-Based Reinforcement Learning
Authors: Herremans Siemen , Anwar Ali , Troch Arne , Ravijts Ian , Vangeneugden Maarten , Mercelis Siegfried , Hellinckx Peter 
Published: September 2023

Abstract
Autonomous shipping has recently gained much interest in the research community. However, little research focuses on inland - and port navigation, even though this is identified by countries such as Belgium and the Netherlands as an essential step towards a sustainable future. These environments pose unique challenges, since they can contain dynamic obstacles that do not broadcast their location, such as small vessels, kayaks or buoys. Therefore, this research proposes a navigational algorithm which can navigate an inland vessel in a wide variety of complex port scenarios using ranging sensors to observe the environment. The proposed methodology is based on a machine learning approach that has recently set benchmark results in various domains: model-based reinforcement learning. By randomizing the port environments during training, the trained model can navigate in scenarios that it never encountered during training. Furthermore, results show that our approach outperforms the commonly used dynamic window approach and a benchmark model-free reinforcement learning algorithm. This work is therefore a significant step towards vessels that can navigate autonomously in complex port scenarios.
High-Order Phase-Resolving Method for Wave Transformation Over Natural Shorelines
Authors: Tsao Wen-Huai , Schurr Rebecca , Kees Christopher E. 
Published: September 2023

Abstract
The use of nature-based facilities has become a popular solution to coastal hazard mitigation and shoreline stabilization. Emergent vegetation, such as mangrove forests, has been proven an effective protective system for alleviating wave and surge impact during a tsunami or tropical cyclone event. To reduce the quantification work and uncertain parameterized equations when modeling the wave height attenuation and momentum dissipation through emergent marsh vegetation, a new approach for implementing a high order Cut Finite Element Method (CutFEM) for problems with embedded solid structures in viscous incompressible flows is presented. The CutFEM allows using the same number of degrees of freedom as the underlying conforming Galerkin method on the fixed background mesh, which is independent of the configuration of non-conforming interfaces. Therefore, it has the same element assembly structure as classical FEM on the background mesh. No explicit generation of cut cell meshes, adaptive quadrature, or local refinement is required. The idea of equivalent polynomials is also adopted to compute the exact integration involving products of polynomials with Heaviside and Dirac distributions. Therefore, this method gains high-order accuracy for embedded interfaces and robustness of the signed distance representation in the level set field. The numerical method that uses a physical model of mock-up mangrove forests is validated through the wave flume experiment conducted by Kelty et al. at OSU. The correlations between the numerical results and experimental measurements are presented. All numerical simulations are completed by the open-source toolkit Proteus.
Analysis of Convergence Behavior for the Overset Mesh Based Numerical Wave Tank in OpenFOAM
Authors: Chen Hao , Qian Ling , Cao Deping 
Published: September 2023

Abstract
This paper presents a solution verification and validation study for an overset mesh based numerical wave tank in Open-FOAM, which considers the coupling between a free-surface hydrodynamic flow model, a rigid body motion model and an overset mesh. The coupling between the rigid body motion solver and the free surface flow solver was achieved in a segregated manner. Free decay of roll motion of a barge was modelled using the numerical wave tank, and the damping coefficient was selected as the target quantity for solution verification. The least square based solution verification procedure was adopted, where one of the four types of error estimators was fit to the data in the least-square sense. Both structured and unstructured mesh were tested, and their effects on the convergence order, numerical uncertainty and error were carefully investigated. From the numerical tests, it is found that the numerical wave tank exhibits a very good convergence property for the floating body problems with structured mesh, i.e. nearly second order in space and first order in time. However, when switching the body-fitted mesh to unstructured mesh, the grid convergence is reduced to first order. Unstructured mesh does not significantly affect the convergence order in time domain, but results in a larger uncertainty due to data scattering.
Dynamic Response of a Taut-Moored Floating Oscillating Water Column Wave Energy Converter in Extreme Waves
Authors: Gubesch Eric , Abdussamie Nagi , Penesis Irene , Chin Christopher 
Published: September 2023

Abstract
This paper presents the results of an experimental investigation into the dynamic characteristics of a 1:36 scaled Oscillating Water Column (OWC) Wave Energy Converter (WEC). Two mooring configurations were tested, namely a vertical taut mooring (i.e., tension leg) and a taut mooring with 45° tendons. The tested sea state was based on conditions that were observed during Tropical Cyclone Oma in 2019 and was re-generated in the physical wave tank with NewWave theory. The orifice used to model the OWC’s power take-off system during operational sea states was closed to simulate the WEC in the shut-down condition. Detailed analysis included the OWC WEC’s rigid body motions (i.e., heave, surge and pitch), OWC chamber pressures, and mooring/tendon tensions. The model with both mooring configurations was found to exhibit similar heave motions, however the tension leg mooring demonstrated a larger surge response whereas the 45° taut configuration demonstrated substantially larger pitch rotations. Mooring lines/tendons in both mooring configurations experienced similar maximum tensions, however the occurrence of peak loads relative to the mooring configuration tested could take place in the forward or aft moorings. For instance, the forward moorings of the 45° taut configuration produced an average peak tension of 79.640 N, whereas the aft tendons for the tension leg configuration produced an average tension of 80.725 N. The load distribution between the forward and aft moorings for the tension leg configuration was similar and showed a difference of 8.3%. However, a much larger variation was observed with the 45° taut configuration where a 39.7% reduction was observed between the forward and aft moorings. Finally, a very high-frequency response was observed in the time history (during and post wave impact) of both the forward and aft tendons of the tension leg mooring configuration. Interestingly, the high frequency response was not observed in the 45° taut configuration.
A Risk-Based Fire Protection Design of a LNG Fueled Ship
Authors: Kim Hyunpyo , Nam Hyunjoon , Kang Ga Hyeong , Kim Min Joo , Kim Sunghee , Shin Dongkyu , Park Sung-In 
Published: September 2023

Abstract
Due to cryogenic and flammable nature of LNG, the LNG-fueled ships require the risk assessment for the safety designs against the release of LNG during operation. Fire is a major accident resulting from LNG leak and the rational fire protection can be achieved by considering the probability and consequence of fire, i.e., the risk of fire. However, the current fire protection of the LNG-fueled ship depends on the prescriptive approach and this may lead to an unreasonable design of the ship. The validity of the fire protection requirement has been questioned and this paper proposes the need for the risk-based design approach. An LNG-fueled product carrier is developed and uncertainty on the interpretation of a part of the fire protection requirement in the design standard is discussed. Using a quantitative assessment technique, a fire risk is estimated and the results are presented through a risk contour which is expressed as a combination of a specific fire intensity and frequencies of fire occurrence. As the result of the risk assessment study, an affordable fire protection design is adopted and the findings of this paper are summarized in relation to the needs for the risk -based fire safety design of the LNG-fueled ship.
Optimised Wave-by-Wave Prediction of Spread Waves: Comparison With Field Data
Authors: Hlophe Thobani , Taylor Paul H. , Kurniawan Adi , Orszaghova Jana , Wolgamot Hugh 
Published: September 2023

Abstract
Real-time forecasting of ocean surface waves can be beneficial for many offshore operations such as ship navigation, load mitigation on floating offshore wind turbines, and control of wave energy converters. This study validates a linear, algebraic prediction model for sea states with large directional spreading. The model decomposes observed time histories using a Fourier transform to obtain an approximate representation of the wave field using a small number of directional components. Pre-processing involves the partial removal of nonlinear harmonics by a bandpass filter followed by the attachment of a NewWave-type signal at each end of each record. The model is tested using field data measured using a small array of wave buoys deployed in the Southern Ocean off Albany, Western Australia. It shows good agreement between prediction and target time series. Aggregating and weight-averaging multiple predictions obtained with different sets of optimal representative directions improves the quality of prediction. Based on the linear propagation of representative directional Fourier components, the model is relatively robust to the presence of (unfilterable) higher harmonics and fast enough for real-time predictions.
Detection of Long-Term Changes in Mooring Stiffness Using Vessel Position Monitoring
Authors: Eassom Adrian , Jayasinghe Kanishka , Thomas Clare 
Published: September 2023

Abstract
In recent years there has been a growing appreciation in the offshore sector of the importance of developing reliable and robust methods to continuously monitor the integrity of floating production system moorings. Development efforts have mainly focused on detecting mooring failures which result in changes in the behaviour of the floating structure within a short time scale. However, these monitoring system technologies can also be leveraged to detect degradation in mooring system performance over longer time scales. The stiffness of a mooring system can be influenced by several factors including creep of synthetic rope, damage to rope construction, interlink wear of mooring chain, seabed trenching of mooring lines, excessive marine growth and loss of clump weights on mooring lines. Such changes in stiffness can change the dynamic response of the floating structure, potentially increasing the offset in extreme sea states beyond the allowable design offset limits.
Hardware that measures mooring line loads or departure angles as a direct means of monitoring for mooring line failures can also be used to detect changes in mooring line pre-tension and therefore monitor for long-term changes in mooring stiffness. However, such hardware (load cells, inclinometers, sonar systems, strain gauging, etc.) can be expensive to retrofit, costly to maintain and suffer from long-term reliability issues. This has led to the implementation of solutions using Global Navigation Satellite System (GNSS) vessel position data as a more cost-effective and reliable alternative for real-time mooring integrity monitoring. There are multiple methods by which a GNSS-based integrity monitoring system can be programmed to detect mooring failures, most commonly by employing machine learning models. This paper presents a method to extend a machine learning model used for a GNSS-based integrity monitoring system to also monitor for changes in mooring system stiffness, by leveraging the use of a digital twin and assessing long-term changes in measured excursions. This method will be demonstrated via a case study for a spread-moored floating facility.
Application of Insulated Drill Pipe to Supercritical/Super-Hot Geothermal Well Drilling
Authors: Kohei Ajima , Naganawa Shigemi , Bjarkason Elvar Karl 
Published: September 2023

Abstract
In Japan, a research and development project is ongoing that is aimed at developing supercritical geothermal exploration and power generation methods. The extremely high formation temperatures encountered during supercritical geothermal drilling presents a challenge for the durability of downhole tools. Thus, it is essential to design an effective method of downhole cooling during drilling. To protect commonly used downhole tools from thermal damage, the objective is to reduce the downhole temperature in supercritical geothermal wells to below 175°C, which coincides with the lowest heat resistant temperature of most downhole equipment. In this study, the authors carried out numerical simulations focusing on the effectiveness of using insulated drill pipes to reduce downhole fluid circulation temperatures during drilling through formations with temperatures high enough for a supercritical reservoir. It was found that use of insulated drill pipes effectively controlled the downhole temperature by reducing the heat influx conducted from the formation. Considering the additional cost of using insulated drill pipes, we also looked at cases where the insulated drill pipes were only applied along two-thirds of the entire drillstring. Considering the flow rate of the circulating fluid and the inflow temperature, the temperature simulation was performed to keep the downhole temperature below 175°C. We also considered the additional pressure loss that could be expected from using the narrower insulated drill pipe.
Numerical Investigation of the Statistics of Vertical Bending Moments of Ships in Nonlinearly Evolving Irregular Waves
Authors: Houtani Hidetaka , Matsui Sadaoki , Fujimoto Wataru 
Published: September 2023

Abstract
This study investigated ship response statistics in waves evolving due to nonlinear quasi-resonant interactions. For that purpose, a nonlinear strip method, NMRIW-II (nonlinear motion in regular and irregular waves), has been extended such that nonlinear wave fields precomputed by the higher-order spectral method (HOSM) can be input. In the numerical simulation, the significant wave height and nonlinear order of the input irregular waves were varied to investigate the impact of wave nonlinearity on ship responses. Furthermore, a container ship and a wall-sided ship were used in numerical simulations to separate the nonlinearity influences attributed to the hull geometry and wave. The lengths, breadths, drafts, and water plane geometries were the same between these ships. The numerical results revealed that the body (hull-geometry) nonlinearity enhances the tail of the sagging moment peak probability distributions. Furthermore, an increase in large wave occurrence due to nonlinear quasi-resonant interaction was revealed to further enhances the tail of the sagging moment peak probability distributions.
Hydrodynamic Performance of a Conceptional Seatrain in Heading Wave Based on Small Water Plane Area Trimaran
Authors: Qin Yan , Wang Qing , Dong Guohua , Yao Chaobang , Feng Dakui 
Published: September 2023

Abstract
Seatrain is a new concept to reduce resistance by using a system that connects multiple ships to achieve broader ocean transportation and ocean warfare. In order to take realistic sea conditions into consideration, the hydrodynamic performance of sea train in heading wave based on multiple identical small-water-plane-area trimarans arranged in a straight line is systematically investigated in present study.
Firstly, present numerical method is validated through the comparison of computational and experimental results of a small-water-plane-area-twin-hull in waves, and good agreement can be obtained. Therefore, the resistances, heave and pitch motion of the single trimaran in wave at different speeds from 0.7m/s to 2.8m/s are obtained using STAR-CCM+. Afterward, in order to investigate the interaction of seatrain system, two or three identical trimarans are arranged in a longitudinal column navigating in regular wave. There are two approaches conducted separately, in which trimarans are physical connection or non-connection. The numerical solution is evaluated with two connection approaches and compared with single ships with the same velocity and wave condtion. The result shows that the train composing a very long, slender hull form can increase transportation efficiency and maximum speed by reducing resistance. Meanwhile, the resistance of each hull while operating as a two-ship-train and a three-ship-train is compared with hydrodynamic performance of the single ship. Through the systematic analysis, the characteristics and laws of hydrodynamic interference to minimize the collective resistance of its system are obtained.