bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of Ship-Ice Interaction in Pack Ice Area Based on CFD-DEM Coupling Method
Authors: Zou Ming , Tang Xiang-Jie , Zou Lu , Zou Zao-Jian 
Published: October 2022

Abstract
Global warming has caused significant changes in the environment of the Arctic. Due to the shipping economy and efficiency, the number of ships sailing in the Arctic region has been increasing recently. Since pack ice is a common ice condition in the Arctic, studying the ship-ice interaction in the pack ice area is significant to the ship navigation in this area. This paper applies the fluid-ice coupling method combining Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) to establish the numerical model for investigating the ship-ice interaction in the pack ice area, considering the influence of flow field. Based on the CFD-DEM coupling method, the ship-ice interaction is simulated for the KRISO Container Ship (KCS). Through the comparison with the results of empirical formulae and experimental measurements, it is found that the numerical model can not only predict the ice resistance more accurately, but also simulate the typical phenomena of ship-ice interaction. Besides, the influences of ice concentration and ship speed on the ice resistance, and the impact of ship-generated waves on the motion of pack ice are studied.
Risk Assessment of Collision Between Dynamically Positioned Vessel and Offshore Installation
Authors: Chen Haibo , Nygård Bjørn , Hasund Nils 
Published: October 2022

Abstract
DP vessels are serving offshore installations for various purposes, but they may also bring major accident risk during the operation if a collision between vessel and installation happens. A quantified collision risk assessment methodology for DP vessels visiting offshore installations is developed. The methodology is based on the risk assessment framework defined in ISO31000:2018, and it consists of three elements: risk identification, risk analysis in terms of collision likelihood and collision consequence, and risk evaluation. The methodology accounts for the physics of DP vessels, the reaction time characteristic of human operators and other aspects in position loss and collision scenarios. The likelihood of collision and the consequence of collision, in terms of exceedance probability distribution of impact energy relevant for collision damage, are interrelated and calculated by using a Monte Carlo simulation model. The methodology provides a more accurate risk picture and better support for risk treatment than the collision risk study purely based on the historical collision frequency and the historical collision energy distribution. For risk evaluation the methodology proposes an alternative way of presenting the risk results in terms of “Risk Density”. It is essentially an hourly, instead of yearly, averaged risk level during the marine operation. It helps better visualization and communication of the collision risk between vessel and installation to stakeholders and decision makers. A case study is presented to illustrate the methodology and concept. It assesses the collision risk between a DP shuttle tanker and an FPSO during offshore loading operations.
Wave Drift Forces and Low Frequency Drift Motions for Mooring Analysis of a Spread Moored FPSO
Authors: Zhang Min , Xu Nuoya , Yang Tianen , Fonseca Nuno , Mood Fredrik 
Published: October 2022

Abstract
This paper presents a comparison study on wave drift models as well as corresponding low frequency (LF) drift motions for mooring analysis of a spread moored FPSO in moderate seastates with and without current. There are four wave drift force models applied in this study, including two numerical models from potential theory with Newman’s approximation and full quadratic transfer functions (QTFs), two combined models determined from cross bi-spectral (CBS) analysis of model test data and merged with two numerical potential flow wave drift force models at low and high frequencies, respectively. The comparison is performed in terms of both diagonal and off diagonals with constant difference frequency.
The equations of motion are solved in the time domain with a fully coupled method, accounting for different wave drift forces models. Both the LF motion response spectra and the time domain series are presented and discussed. The LF damping is adjusted by comparing simulations to the corresponding model test data and tuning the results. The results show the underestimates of wave drift forces as well as the corresponding LF motions by second order potential flow theory, especially in the cases with current. Application of full QTFs can improve the simulation results in terms of phasing of LF responses.
Finite Element Modeling of the Effect of Different Post-Weld Heat Treatment on Strength of Welded AISI 4130 Steel Pipe
Authors: Englund Even 
Published: October 2022

Abstract
AISI 4130 steel is a low-alloy strength steel and is a popular choice for fabrication of drilling fluid pipes in the oil and gas industry. One of the drawbacks of this low-alloy steel is that it can form martensite at relatively low cooling rates during welding, which is why the welds in this steel require post-weld heat treatment (PWHT) to temper the martensite in the heat-affected zone (HAZ). While tempering martensite in the HAZ, the heat treatment might also lead to weakening of the base material near the weld in cases where the heat-treatment temperature is too high. In 2014 the PWHT procedure for welded pipes in the ASME Code (ASME B31.3) was changed and the maximum allowed PWHT reduced. Hence, according to the new standard, older welds have been heat treated at temperatures that are too high.
The present article investigates the strength of AISI 4130 steel undergone different PWHT and uses the finite element method to model pipe failure in order to investigate the possible effects of the old heat-treatment procedure on pipe strength. The effect of the different PWHT temperatures on the base material strength is investigated through tensile tests of samples undergone different heat treatments. Then, from the extracted material data from the tensile tests the pipe is modeled and analyzed through explicit finite element method to evaluate what effect the anticipated material weakening from the old PWHT procedure has with regard to pipe strength and integrity.
Calibration for Interpretation Parameter Nkt of CPTU in Offshore Wind Farm at Coast Area of the Mekong River Delta
Authors: Wang Kuanjun , Liu Gang , Shen Kanmin , Gao Shan 
Published: October 2022

Abstract
Sample disturbances during drilling work in offshore wind farms are inevitable due to the marine environment, and much higher than those in onshore projects, which would lead to an underestimate of soil strength, especially for soft clay. Piezocone penetration test (CPTU) is now widely used in the geotechnical investigation in offshore wind farms, which has slight the disturbance on soil. But the soil parameters cannot be directly obtained by CPTU, and the interpretation process should be carried out, while the parameters for interpretation are site-specific. Based on an offshore wind farm at the coast area of the Mekong River Delta in Vietnam, laboratory tests and CPTU results are analyzed to calibrate the cone factor Nkt, which is used for CPTU interpretation of undrained shear strength su. The calibrated Nkt from the triaxial UU test, which ranges from 10.82 to 57.89, is much higher than the calibrated Nkt values from DSq and triaxial CU test. A possible reason is that the soil samples for triaxial tests were disturbed during drilling and transportation, the triaxial UU tests might underestimate the strength of in-situ clay. The cone factor Nkt calibrated from the DSq test and triaxial CU test respectively range from 15.65 to 25.86 and 12.51 to 30.50, with the total average value of 22.29 and 20.44, which are more accurate compared to the Nkt values calibrated from the triaxial UU test. Finally, a negative correlation between pore pressure ratio Bq and Nkt is established based on triaxial CU test results, which can be used to choose the appropriate Nkt value for interpretation. The CPTU interpretation by Bq-Nkt correlation and the total average value 20.44 of Nkt both show good agreement with the measured soil strength. For simplicity, the total average value of Nkt calibrated from triaxial CU test results is recommended to be used for the CPTU interpretation in engineering projects, which is more convenient.
Cyclonic Wave Field in the Bay of Bengal Region Under Changing Climate Scenarios
Authors: Bhavithra R. S. , Sannasiraj S. A. 
Published: October 2022

Abstract
Wind-wave plays a major role in the planning and designing of important coastal structures. The study on wave characteristics is considered necessary for the routing of ships, wave hindcasting and forecasting. Climate change is one of the major threat that has been occurring over the years and the impact of climate change on wave climate results in increased storm effects and rough sea conditions. Bay of Bengal (BOB), an active cyclonic region along the North Indian Ocean experiences severe storms every year during the north-east monsoon season. Hence, an understanding of wind-wave climate under cyclonic storms in the BOB region is essential. The present study considers three severe cyclonic storms in the BOB region: Phailin which occurred during October 2013; Hudhud during October 2014; and, Vardah during December 2016. The study further details about the impact caused by these cyclone when projected to the future under the climate change scenarios. The wave climate of the three considered cyclones is projected for the Representative Concentration Pathway (RCP) scenarios of RCP4.5, RCP6.0 and RCP8.5 under both for the Near-Future (2035) and Far-Future (2075) categories. The domain covering the BOB region is discretized with a resolution of 0.25°x0.25°. The surface wind of the chosen domain for the projected scenarios is obtained from the Weather Research and Forecasting (WRF) model and then these winds are forced into the WAve Model (WAM) to predict the corresponding wave climate. The significant wave height (Hs) obtained from the WAM model for the projected scenarios has been compared to the present scenario of the respective cyclones and the results show an increase in intensity for all the three cyclones under the Far-Future categories of RCP6.0 and RCP8.5 scenarios. The wave climate under Hudhud cyclone has the greatest intensity of about 21% under the Far-Future category.
Consistency Assessment of Wave Directional Spectrum Predictions From Machine Learning Based Ship-As-a-Wave-Buoy Methods
Authors: Scholcz T. P. , Düz B. , Hageman R. B. , Mak B. 
Published: October 2022

Abstract
Real-time knowledge of the ocean wave directional spectrum is valuable for maritime safety and navigation. When end-to-end machine learning is used to learn ocean wave directional spectra from ship motions, the spectrum predictions may be inconsistent with measured ship motions from a physical point of view. In order to assess this consistency, a method is proposed that makes use of a numerical seakeeping code to recalculate ship motions from predicted wave spectra. The recalculated ship motions are subsequently compared to the measured ship motions. The method is applied using data from three different vessels, each having a different level of data completeness. For these cases it is concluded that the consistency can be assessed when the sea state is not too extreme. The method may be improved by using higher fidelity seakeeping codes.
Motion Characteristics of a Floating Model With Moonpools for VAWTs
Authors: Ikoma Tomoki , Fujishima Katsuhide , Aida Yasuhiro , Lei Tan , Masuda Koichi 
Published: October 2022

Abstract
This paper describes motion behaviors of a floating body and water regions of moonpools. The floating model to be focused in this study has moonpools and is for offshore wind turbine system with two vertical axis wind turbines. Motion behaviors of water region in moonpools strongly affect on motion characteristics of a floating body itself. Often the effects lead to non-linear motion of the floating body. Besides, when the floating body is a system of vertical axis offshore wind turbines, the system becomes more complicated.
This study conducted theoretical calculations and model experiments in a wave tank. Behaviors of moonpools were measured in regular waves and we measured wave exciting forces, radiation forces on heave and motion responses of the floating model. Also, the study considered effects of Vertical Axis Wind Turbine (VAWT) model’s rotation on the motion.
From the results behaviors of moonpools were often nonlinear to incident waves and the behaviors affected on motion responses of the floating model. The experimental results were compared with the calculation results. When non-linearity due to overtopping of water from moonpools was found, the calculations could not reproduce hydro forces but they are able to estimate motion responses. The study confirmed reduction effects due to the moonpools on motion responses comparing with a conventional pontoon with identical displacement.
Numerical Analysis of the Efficiency of Corroded Pressure Vessels With Composite Repair
Authors: Drumond Geovana , Ribeiro Rodrigo , Pasqualino Ilson , Lourenço Marcelo Igor , Perrut Valber , Lana Luiz Daniel 
Published: October 2022

Abstract
This paper is part of a research project that is concerned with the assessment of the efficiency of composite repair in corroded metallic pressure vessels. The focus is to evaluate localized repairs in corroded areas near nozzles. A numerical model was developed, and the results were validated against experimental tests. 50%, 70%, and 80% wall loss defects were manufactured into small-scale metallic vessels in two different positions and the failure pressure of the repaired vessels was determined using hydrostatic tests. The numerical results show that the failure pressure of the repaired vessel is close to the non-defective vessel, showing that the repair system was efficient.
Full Scale CFD Validation Using Ship Performance and Wave Pattern Measurements of a Mega Cruise Ship
Authors: Schouten D. R. , Drouet A. , Birvalski M. , Morand L. 
Published: October 2022

Abstract
The shipping industry is directly impacted by the global challenge of reducing greenhouse gas emissions. Improvements can be achieved by hull form optimization when designing new ships. Computational Fluid Dynamics (CFD) is nowadays regularly applied for basic resistance simulations as well as for e.g. self-propulsion with rotating propellers or maneuvering in waves. In order to avoid scale-effects, it is increasingly common to perform ship scale CFD calculations. Unfortunately, the available full scale data that can be used for validation are limited. Specifically, flow velocity and radiated wave pattern data are rare at full scale because of the complexity of performing such measurements. Nevertheless, in the current work, full scale wave pattern measurement were performed on a 330 meter long cruise ship sailing at 20 knots using the Digital Image Correlation technique. This is an image analysis method capable of measuring deformations of a surface in space. The approximate size of the field of view was 75 m by 30 m. The ship’s speed, shaft power, propeller rate, motions and environmental waves were measured as well. Additionally, Reynolds Averaged Navier-Stokes (RANS) simulations were performed using STARCCM+. The propeller was modelled both as an actuator disk as well as a rotating propeller with a sliding interface. The turbulence closure model was k-ω SST and the free surface was modelled using the Volume of Fluid method. The balance between hull resistance and propeller thrust was verified as a first step, showing less than 4.0% difference. The power determined by CFD was validated against the one measured during the sea trials with less than 3.6% difference. Finally, the comparison of the stern wave pattern resulting from full scale CFD simulations with the pattern measured using DIC showed excellent agreement with good accuracy.
Challenges in the Implementation of the Air Injection EOR Method: The Venezuelan Experience
Authors: Rodriguez M. Fernancelys 
Published: October 2022

Abstract
Air Injection, or in-situ combustion (ISC), is one of the oldest thermal EOR methods that has been applied in Venezuela to increase the production of highly viscous crude oils, with a first field application in 1959 in the Tia Juana Field-Lake Maracaibo Basin. This method, which is characterized by a high energy efficiency, consists of injecting air into the reservoir where exothermic oxidation reactions are initiated to increase the mobility of the oil by reducing its viscosity and increasing the API gravity. Compared to other thermal EOR methods such as steam injection, the air injection method has a lower environmental impact in terms of water and fuel consumption, and emission of gases, as the produced gases can be reinjected or stored.
According to the literature, several air injection projects have been carried out in Venezuela in Tia Juana, Morichal, Miga and Melones fields. Although the technical results have been satisfactory in terms of viscosity reduction and improved crude oil properties (such as °API), other important aspects of project evaluations have not been convincing due to the following factors: operational problems, high temperatures in producing wells, corrosion, and high CAPEX and OPEX costs in low oil price environment, among others. Nevertheless, a recent literature survey has shown that additional research works have been conducted on process optimization, using solid and liquid catalysts to better address the other factors mentioned.
Due to the great need to increase hydrocarbon production in Venezuela, and to the advantages of air injection as an upgrading technique where low-carbon fuels and hydrogen as by-products are generated, this paper presents a review of the air injection projects in Venezuela from research aspects and field applications. This paper seeks to identify the main insights on success and failure of ISC projects and make substantiated recommendations in case of future application of this technology.
A Green and Environmentally Friendly Chelated Retarding Acid for Acidification of Sandstone Reservoirs
Authors: Wei Liu , Qing Wang , Changfeng Xu , Mengchuan Zhang , Xinmin Kong , Erdong Yao , Junren Que 
Published: October 2022

Abstract
Matrix acidizing is the main method to relieve formation damage in sandstone reservoirs. However, many problems in conventional mud acid acidification need to be carefully considered, such as fast acid-rock reaction, short effective action time, excessive dissolution near the well zone, and the secondary sedimentations from fluorosilicic acid, aluminosilicate, calcium fluoride and other pollution of the reservoir.
In this paper, a green and degradable amino acid chelating agent is investigated. This new type of sandstone chelating retarded acid system have features of chelating metal ions and slow proton release. The chelating ability of new retarder acid to calcium and iron metal ions was determined by complexometric titration. The retarding performance of chelating retarder acid were studied by core flow instrument and microscopic scanning electron microscopy. The results show that the new acid system is manifested by strong chelating ability to iron and calcium ions, low corrosion rate, good retarding performance. The permeability is increased by 225% after acidification. The results of electron microscopy scanning of the core surface before and after acidification show that the new acid solution acidification can effectively enlarge the pore-throat without generating secondary precipitations, which is a good choice for sandstone acidification practice.
Methodology for Defining Risk Indices Applicable to Subsea Equipment
Authors: Maturana Marcos Coelho , Schleder Adriana Miralles , Frutuoso e Melo Paulo Fernando Ferreira , Martins Marcelo Ramos , de Barros Leonardo Oliveira 
Published: October 2022

Abstract
As offshore operations explore deeper and deeper reserves, there may be an increase in the number of accidents and failures, resulting in greater challenges for the sustainability of these operations. In this sense, the planning of inspections and maintenance of subsea equipment assumes a central role, both in terms of costs and in relation to the risks involved. Risk Based Inspection (RBI) appears as possibility to address these challenges, and have been more and more employed to assist the operators in finding cost-effective solutions while considering safety aspects.
For the effective application of RBI tools, it is necessary to calculate the risk in order to facilitate the comparison of inspection plan alternatives, also allowing the comparison of each possible solution risk with a Risk Acceptance Criteria (RAC) accepted by society. In this sense, this paper discusses a risk calculation method that can be used in the quantitative optimization process (aimed at improving subsea equipment inspection plans), considering the inspection plan as a whole, the general characteristics of the equipment and its operation, and a RAC.
Fracture Toughness Characterization of LSAW UOE Pipes in Sour Media and Implications on Burst Pressure
Authors: Cravero S. , Coloschi M. , Valdez M. , Arroyo F. , Darcis Ph. 
Published: October 2022

Abstract
Large diameter Sour Service Pipelines are designed for the safe and efficient transportation of production fluids containing H2S. This service condition exposes the pipe to hydrogen embrittlement mechanisms and demands a material with high Sulfide Stress Cracking (SSC) resistance, and thus, a high fracture toughness in a representative sour environment.
Engineering Critical Assessment (ECA) procedures are usually employed to determine the suitability of a pipeline design, these procedures require the correct determination of the material fracture mechanical properties.
Although Method D of NACE TM0177_16 [1] using DCB specimens is currently a recognized testing methodology to evaluate SSC pipe performance, other type of tests could be employed for the purpose of an ECA.
In the present paper, a fracture mechanics experimental program in sour environment is presented. Parent Pipe and Weld Material of Longitudinal Submerged Arc Welded (LSAW) large diameter pipes in H2S were studied. Fracture Toughness Parameters, such K-limit from standard DCB tests and K-threshold from Single Edge Notch Tension (SENT) specimens under constant loading, are compared and discussed. Furthermore, the fracture toughness values obtained from SENT specimens in sour environment are used to estimate the burst pressure using an ECA procedure.
Development of Design Procedure for LNG Carriers With IMO Type-B Independent Tank
Authors: Kim Beom-il , Islam Md Shafiqul 
Published: October 2022

Abstract
There is a growing interest in applying the technology to small and medium-sized Liquefied Natural Gas (LNG) carriers to meet the recent increase in demand for LNG as an ecofriendly fuel and for expanding LNG bunkering infrastructure. The purpose of this study is to apply the IMO Type B tank to small and medium-sized LNG carriers and verify the safety and suitability of the design. One of the key technical issues of Type B LNG tank is heat transfer analysis and selection of hull steel grade. In this study, a heat transfer analysis was performed for hull temperature calculation and steel grade selection. Also, the stress levels and the thermal movements of the tank were checked through thermal stress analysis applying thermal and mechanical loads. Another key technical issue of a Type B tank is to determine the size of a partial secondary barrier based on fracture mechanics. For the accurate analysis, a procedure was developed and verified based on direct analysis and international regulations. Finally, the related safety and suitability of the IMO Type B for LNG cargo tanks required by International Gas Carrier (IGC) code were verified. Two key technical issues with applied examples are thoroughly analyzed in this study, could be applied in the design of independent Type B LNG carrier.