bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Investigation of an Experimental Ocean Current Turbine Based on Blade Element Momentum Theory (BEM)
Authors: Sadeqi S. , Rouhi S. , Xiros N. , Aktosun E. , VanZwieten J. , Sultan C. , Ioup J. 
Published: October 2021

Abstract
Ocean currents are one of the alternative sources of green, sustainable, and renewable energy that could generate low-cost electric power without any pollution due to the burning of fossil fuels. Due to the density of the water, ocean currents can produce a significant amount of energy even with a very small current velocity field. In this study, a comprehensive performance analysis of 3-blade horizontal-axis Ocean Current Turbine (OCT) is shown to achieve optimal rpm (revolutions per minute) to match environmental conditions in order to harvest the maximum possible energy from OCT in ocean currents. Our approach is to use Blade Element Momentum (BEM) theory in order to estimate hydrodynamic loads for the turbine; specifically, the design of the OCT blades is based on a FX77-W121 type airfoil. We use JavaFoil to analyze and determine hydrodynamic lift and drag coefficients with respect different angles of attack for the hydrofoil profiles in seawater. After validation of blade design characteristics and obtaining the local coefficients of each hydrofoil cross-sections, we transfer them to our in-house-developed Blade Element Momentum Theory (BEM) code in order to achieve the estimation of performance analysis of the OCT in order to get maximum power and ideal torque and thrust. This performance analysis with BEM model of the OCT is an important step for further analysis due to having different incoming flow speeds in actual time-varying sea conditions. Indeed, the OCT will encounter different incoming ocean current speeds during operation. Therefore, this approach is used to get an accurate brake power estimate of the OCT in different operational current speeds. In addition, this performance analysis of the OCT is going to be utilized in designing and developing a test model for the physical towing tank experiment for later investigation.
Thermal Design of Pipelines – A Challenge for Flow Assurance in the Arctic
Authors: Ponagandla Veerendhar , Liu Liangjian , DeGeer Duane 
Published: October 2021

Abstract
Increasing demand for energy is driving the need to explore the deeper oceans and the far north. While higher temperature, pressure and longer tie-backs are challenges going deep, highly sensitive environment is an issue exploring far north. The discovery of large reserves in the far north has brought the challenges of exploration, production, and transportation in the cold regions like Prudhoe Bay, the Mackenzie Delta, and the Arctic Islands into focus. To transport hydrocarbons to market, pipelines used in the Arctic have unique challenges and stringent design conditions that must be met to ensure reliable operations in such remote and sensitive environments.
To avoid flow assurance risks, the adage “the hotter the better” is in stark contrast to the sensitive nature of the Arctic environment to temperature changes, and where “the colder the better” is more appropriate. Permafrost, and its potential disturbance, is the most important factor to be considered for pipeline thermal design. High temperatures can disturb the in-situ state of the permafrost, causing settlement and instability in the permafrost zone. Also, high pipeline temperatures demand deep trenches to avoid melting the surface ice, challenging installation and increasing CAPEX.
Designing the pipeline to maintain high internal fluid temperatures to reduce flow assurance risks and lower pipeline outer temperatures to minimize the impact on the environment is the best solution. To maintain high fluid temperatures and reduce heat loss to the environment, the conventional idea of a high value insulation like pipe-in-pipe with a vacuum annulus to avoid heat loss to the sensitive Arctic surroundings may seem to be a good solution, but it may not be the optimal solution. This paper discusses a hypothetical scenario (based on field cases) of a multiphase pipeline design and highlights the associated flow assurance/operational risks.
Pre- and Post-Tsunami Depth Changes of Submarine Topography for the Analysis of Submarine Landslide-Induced Tsunami: Proposal of Digitization Method and Application to the Case of the 1923 Great Kanto Earthquake Tsunamis
Authors: Murata Kazuki , Sassa Shinji , Takagawa Tomohiro , Ebisuzaki Toshikazu , Maruyama Shigenori 
Published: October 2021

Abstract
We first propose and examine a method for digitizing analog data of submarine topography by focusing on the seafloor survey records available in the literature to facilitate a detailed analysis of submarine landslides and landslide-induced tsunamis. Second, we apply this digitization method to the seafloor topographic changes recorded before and after the 1923 Great Kanto earthquake tsunami event and evaluate its effectiveness. Third, we discuss the coseismic large-scale seafloor deformation at the Sagami Bay and the mouth of the Tokyo Bay, Japan.
The results confirmed that the latitude / longitude and water depth values recorded by the lead sounding measurement method can be approximately extracted from the sea depth coordinates by triangulation survey through the overlaying of the currently available GIS map data without geometric correction such as affine transformation. Further, this proposed method allows us to obtain mesh data of depth changes in the sea area by using the interpolation method based on the IDW (Inverse Distance Weighted) average method through its application to the case of the 1923 Great Kanto Earthquake. Finally, we analyzed and compared the submarine topography before and after the 1923 tsunami event and the current seabed topography. Consequently, we found that these large-scale depth changes correspond to the valley lines that flow down as the topography of the Sagami Bay and the Tokyo Bay mouth.
3D Laser Scanning for Thickness Measurements of Hull Structures
Authors: Zhang Xi-Ying , Loader Charles , Schilling Spencer , Hernandez Vicente , McSweeney Kevin , Gu Hai 
Published: October 2021

Abstract
3D scanning technology uses lasers to scan and capture object surfaces without physical surface contact. Laser scanning is gaining acceptance by many, including owners of marine or offshore assets as a viable inspection and validation method. Laser technology reduces operational times compared to traditional pit gauging techniques, particularly for large areas of widespread wastage or pitting. This paper studies the use of 3D scanning technology for inspection, thickness gauging, and steel wastage measurements of hull structures.
Pilot tests were conducted on coated and uncorroded plates in Houston, USA, and uncoated and corroded plates and uncoated and deformed plates in Perth, Australia. Manual Ultrasonic Testing (UT) was conducted, which is the method currently accepted by International Association of Classification Societies (IACS) for thickness measurements of hull structures. For the coated plate, the coating thickness was measured on both sides of the plate. The coating thickness was deducted from the total thickness from 3D scanning before the plate thickness was compared with the UT results.
Acceptance criteria are proposed to compare the Manual UT measurements with the 3D scanning measurements to determine if 3D laser scanning is a possible alternative thickness measurement method. The difference of thickness measurements from 3D scanning on coated and uncorroded plates is within 13% when compared with those from UT. The discrepancy is attributed to equipment accuracy tolerances, errors from data post-processing, and measurement errors due to coating surface roughness. For uncoated and corroded plates, the difference reduces to 3%, making the results of 3D scanning acceptable based on acceptance criteria. In addition, the higher accuracy of using 3D scanning to measure plate deformation is demonstrated over traditional methods which use stringlines or laser levels to create a reference surface. Comparisons of the coefficient of variation (CV) on all plates demonstrate the higher precision of 3D scanning technology than that of manual UT. The main limitation of 3D laser scanners is their inability to directly obtain steel thickness for structures that have been coated or painted, especially in watertight/oil-tight structures.
The study identifies capabilities, accuracy, and limitations of using 3D scanning technology for thickness measurements of hull structures in the marine or offshore industries. Scanning technology can support inspections providing fast and precise means of thickness measurements of corroded plates without coating. It provides the potential for producing 3D models and analysis for follow-up inspections. Plausible use cases in the maritime industry include defect analysis, fitness for service assessment, damage assessment, and corrosion monitoring.
Effect of Geometric Parameters of New Semisubmersible Platform on Stability and Hydrodynamic Performance
Authors: Wang Tianying , Zhou Yanjun , Tang Honglin , Zhang Shihua , Tian Haiqing 
Published: October 2021

Abstract
The JCSM concept (short for Jackup Combined Semisubmersible Multifunction Platform) is a new type of semisubmersible platform presented by the first author, which overcomes the shortcomings of the available semisubmersible platforms, and combines the advantages of the traditional semisubmersible platform, the Jackup platform and the new FPSO concept - IQFP. Due to the complicated interaction between stability and hydrodynamic performance, it is necessary to explore the effect of geometrical parameters of the main body on the stability and hydrodynamic performance in order to obtain the optimal design plan of a JCSM platform. Firstly, the structure components and innovations of the JCSM were briefly reviewed in order to facilitate readers to understand its full picture. Then, six independent geometric parameters were selected by carefully studying the shape characteristics of the initial design plan of a JCSM study case. Furthermore, the stability heights and motion responses of various floating bodies of the JCSM case with different geometric parameters in wave were calculated using boundary element method based on potential flow theory. Lastly, effect of the shape parameters on stability and hydrodynamic performance of the JCSM was qualitatively evaluated. The research would shed lights on the shape design of the JCSM main body.
3D Simulation of Surface Casing Cementing: Dispersion Effects
Authors: Zhang Ruizi , Frigaard Ian 
Published: October 2021

Abstract
Many numerical studies have been conducted regarding laminar miscible displacement flow in narrow, vertical, eccentric annuli. For the next decade it is likely that primary cementing flows on the scale of the well will continue to be simulated predominantly with 2D gap-averaged (2DGA) models. However, 3D simulations are less common due to the computational cost. The comparison between 2D and 3D models needs further attention, to understand the main discrepancies and thus help to understand primary cementing flows better. In this paper, comparisons of 3D against 2DGA model results show a range of interesting different phenomena, e.g. static layers, dispersive spikes, and instabilities. The predictions of the 2DGA model are the same as the 3D results to a degree. In particular, they are consistent with each other regarding the evolving process, interface shape, etc. However, the main difference with the 2DGA concentration arises from dispersion on the scale of the annular gap. From the recent research of Renteria and Frigaard (J. Fluid Mech., vol. 905, 2020) [1], a variety of dispersive effects are the main discrepancy between experiments and 2DGA results as well. We give representative examples of these flows in surface casing geometries and suggest methods for improvement of the 2DGA model.
Physical Modeling and Simplification of FPSO Topsides Module in Wind Tunnel Model Tests
Authors: Huang Zhenjia (Jerry) , Kim Hyun Joe 
Published: October 2021

Abstract
To evaluate wind load on offshore structures, such as FPSO’s, wind tunnel model test is a common industry practice. Configuration of topsides structures and equipment can be very complex, and it is a practical challenge to model all the structural details for wind tunnel model tests. Sometimes, there may be significant modifications to the topsides over FPSO operation life cycle and there may not be detailed topsides drawing for wind tunnel to use in physical model construction. In practice, wind tunnel laboratories have to simplify physical topsides models. They also use metal meshes to cover the topsides modules to compensate for the force reduction due to the simplification. In order to help establish physical modeling practices of wind tunnel model test, we performed extensive tests using a single topsides module. The original topsides module without simplification and mesh was tested first. Then, two simplifications were adopted in the physical model construction. The module was covered with and without metal mesh of different porosities. Thorough test quality assurance (QA) and quality control (QC) were performed to ensure data quality. Test setup, quality assurance (QA) and results are presented in the paper. The results can be used not only for appropriate physical modeling practices of complex topsides modules, but also for validation of numerical predictions such as Computational Fluid Dynamics (CFD), as well as empirical formulas.
Northern Light Offshore Pipeline – Negative Transport Temperature Inside the HDD
Authors: Blasioli Giuseppe , Marchesani Furio , Badalini Maurizio , Luci Vincenzo , Bekkeheien Tove , Helland Arne Ingvar 
Published: October 2021

Abstract
The transport of CO2 through offshore pipelines is one of the last business that the Operators are beginning to face, in line with the coming needs for climate change mitigations.
The scenario for CO2 Capture, Transport and Storage anticipates capture and treatment at local plants, the transportation by ships in a liquid phase at low temperatures (close to −30 °C) to a terminal for the following offshore submarine transportation in a pipeline up to an injection well, for the final (and permanent) storage underground.
In order to optimize the operating costs for CO2 transport via pipeline, and to reduce energy consumptions, no heating is applied from ship to pipeline inlet. In such case, the pipeline will reach approximately a temperature of −30 °C in the initial landfall section.
The design of the offshore pipeline subject to this operating conditions, very cold fluid inside and a sea water temperature slightly over 0°C outside (North Sea), must face the possibility of ice formation around the pipe.
For the Northern Lights project, this possibility has been analyzed and the HDD (Horizontal Directional Drilling) at landfall resulted the only section where the ice formation could jeopardize the pipeline integrity. Detailed assessment for both normal operating conditions and contingency cases has been performed.
In the former case, a steady state thermal analysis with analytical method (thermal resistances) has been applied to calculate both the longitudinal, along the pipeline axis, and radial temperature profile: all the water inside the HDD freezes. Therefore, a water circulation system has been studied to prevent the ice formation. The pumping system required to ensure enough water flow has been dimensioned considering pressure losses inside the HDD. Power consumption in the order of 3 kW is expected.
The breakdown of the pumps has been analyzed in order to determine the available time before the sea water freeze inside the HDD obstructing any circulation. A transient analysis has been carried out simulating the temperature after water circulation arrest. Both analytical and Finite Element Model have been used to calculate the transient process causing water freezing.
Engineering Criticality Assessments of Floating Offshore Platforms Based on Time Domain Structural Response Analysis
Authors: O’Donnell Jeffrey , Kyoung Johyun , Samaria Sagar , Sablok Anil 
Published: October 2021

Abstract
This paper presents a time-domain S-N fatigue analysis and an approach to reliable and robust engineering criticality assessments to supplement or provide an alternative to S-N fatigue assessments of offshore platform structures based on time domain structural response analysis. It also provides recommendations for industry standards to improve guidance for structural integrity assessments of offshore platforms using fracture mechanics.
Demand continues to grow in the offshore industry to attain value from captured operational data for a number of purposes, including the reduction of uncertainties in structural integrity assessments during design and over the operational lifetime of floating offshore platforms. Recent advances in time domain structural analysis technology demonstrate substantially more accurate assessments of non-linear platform loadings and responses with enhanced computational efficiency. The current S-N approach for fatigue design and integrity assessments calculates a fatigue damage factor that does not address how loading occurs over time (ABS, DNVGL-RP-C203).
For the present study, engineering criticality assessments (ECAs) based on fracture mechanics theory (BS 7910) are applied utilizing time-domain loading information theory. The ECA returns the smallest initial flaws that can grow to a critical size during a design lifetime, which can serve as an indicator of acceptability during design, a technical basis for in-service inspection intervals and facilitates asset integrity and life extension assessments. Critical initial flaws are calculated using the Paris Law (BS 7910) and cumulative fatigue crack growth in two ways: with and without an integrated and consistent check for fracture instability. The results are compared with those from S-N fatigue analyses and recommendations are provided.
A Joint-Industry Effort to Develop and Verify CFD Modeling Practice for Predicting Hydrodynamic Coefficients on Bare Riser Surfaces
Authors: Jang Hyunchul , Agrawal Madhusuden , Lee Dongwhan , Xu Wei , Huang Jerry , Jiang Fengjian , Jie Wu , Croonenborghs Eloïse 
Published: October 2021

Abstract
Hydrodynamic force coefficients are important parameters in design and assessment of marine risers. The hydrodynamic coefficients are widely used for assessing marine riser responses due to floater motion excitation and vortex-induced vibrations (VIV). Traditionally, the hydrodynamic coefficients have been obtained from physical model tests on short rigid riser sections. Recently, the offshore industry has started to use computational fluid dynamics (CFD) analysis for predicting the hydrodynamic coefficients due to the recent advancement of CFD software and high-performance computing capabilities, but a reliable CFD modeling practice is requested for CFD analysis to be a more widely accepted prediction tool in the industry. A joint industry effort has been made for developing and verifying the reliable CFD modeling practice through a working group of the Reproducible Offshore CFD JIP. In the working group, a CFD modeling practice document was written based on existing practices already validated for model test data, and verified by blind validations with three CFD practitioners. The first year works are focused on the bare riser with circular cross-section, and the second year work will be extended to the other riser sections such as staggered buoyancy module and straked riser.
This paper presents the working group’s first-year verification activities for a bare riser with circular cross-section. The verification works covers three test problems: 1) stationary simulation in steady current, 2) forced-oscillation in calm water, 3) forced-oscillation in steady current. In the stationary simulation, mean drag coefficient, standard deviation of lift coefficient, and Strouhal numbers are compared. In the forced-oscillation simulation in calm water, the fully-submerged riser section oscillates with a sinusoidal motion, and damping and added mass coefficients are compared. In the forced-oscillation simulation in current, the riser section oscillates in cross-flow direction to the steady current, and lift coefficient and added mass coefficient are compared. By following the modeling practice, the CFD predictions are consistent with each other and close to the model test data for a majority of test cases.
Performance Analysis of Offshore Mono-Pile Wind Turbine Co-Located With Floating Photovoltaic Systems in Shark Bay, Australia
Authors: Bahadori Morteza , Ghassemi Hassan 
Published: October 2021

Abstract
In recent years, as more offshore wind farms have been constructed, the possibility of integrating various offshore renewable technologies is increased. Using offshore wind and solar power resources as a hybrid system provides several advantages including optimized marine space utilization, reduced maintenance and operation costs, and relieving wind variability on output power. In this research, both offshore wind and solar resources are analyzed based on accurate data through a case study in Shark Bay (Australia), where bathymetric information confirms using offshore bottom-fixed wind turbine regarding the depth of water. Also, the power production of the hybrid system of co-located bottom-fixed wind turbine and floating photovoltaic are investigated with the technical characteristics of commercial mono-pile wind turbine and photovoltaic panels. Despite the offshore wind, the solar energy output has negligible variation across the case study area, therefore using the solar platform in deep water is not an efficient option. It is demonstrated that the floating solar has a power production rate nearly six times more than a typical offshore wind farm with the same occupied area. Also, output energy and surface power density of the hybrid offshore windsolar system are improved significantly compared to a standalone offshore wind farm. The benefits of offshore wind and solar synergies augment the efficiency of current offshore wind farms throughout the world.
Burst Failure and Reliability Assessment of X-100 to X-120 Ultra-High Strength Pipes
Authors: Bhardwaj U. , Teixeira A. P. , Guedes Soares C. 
Published: October 2021

Abstract
The burst failure and the structural reliability of ultra-high strength (X-100 to X-120) steel pipelines is investigated analytically based on their elastic-plastic collapse behaviour. Structural models for high strength pipes and codes are adopted from literature and their key features are discussed. The models are verified by burst test data for ultra-high-grade steel pipelines. Two statistical measures are used to compare the accuracy of models for ultra-high strength steel pipes. The most accurate theoretical model for ultra-high strength pipes is identified. Limit state functions are formulated based on the strength models for reliability analysis of ultra-high-grade steel pipelines under operational conditions. Probabilistic models are applied to the basic variables of limit state functions. A First-Order Reliability Method is used to assess the reliability for this category of pipelines followed by a sensitivity analysis that identifies the most significant limit state variables. The results of this study can provide vital measures for design and maintenance planning of ultra-high-grade steel pipelines.