bluuebunny/crossref_metadata_2025_split huggingface dataset:
2D Numerical Study on Wake Scenarios for a Flapping Foil
Authors: Xu Hui-li , Greco Marilena , Lugni Claudio 
Published: October 2021

Abstract
Fishes are talented swimmers. Depending on the propulsion mechanisms many fishes can use flapping tails and/or fins to generate thrust, which seems to be connected to the formation of a reverse von Kármán wake. In the present work, the flow past a 2D flapping foil is simulated by solving the incompressible Navier-Stokes equations in the open-source OpenFOAM platform. A systematic study by varying the oscillating frequency, peak-to-peak amplitude and Reynolds number has been performed to analyze the transition of vorticity types in the wake as well as drag-thrust transition. The overset grid method is used herein to allow the pitching foil to move without restrictions. Spatial convergence tests have been carried out with respect to grid resolution and the size of overset mesh domain. Numerical results are compared with available experimental data and discussed. The results show that the adopted methodology can be well applied to simulate large amplitude motions of the flapping foil. The transitions in the types of wake are consistent with the benchmark experimental data, and the drag-thrust transition of the pitching foil does not coincide with von Kármán (vK)-reverse von Kármán (reverse-vK) wake transition and it is highly dependent on the Reynolds number.
Numerical Simulation of Ship Collision and Validations With Experimental Results
Authors: Wang Xiangbiao , Li Chun Bao , Zhu Ling 
Published: October 2021

Abstract
Ship collision accidents occur from time to time in recent years, and this would cause serious consequences such as casualties, environmental pollution, loss of cargo on board, damage to the ship and its equipment, etc. Therefore, it is of great significance to study the response of ship motion and the mechanism of structural damage during the collision.
In this paper, model experiments and numerical simulation are used to study the ship-ship collision. Firstly, the Coupled Eulerian-Lagrangian (CEL) was used to simulate the fluid-structure interaction for predicting structural deformation and ship motion during the normal ship-ship collision. Meanwhile, a series of model tests were carried out to validate the numerical results. The validation presented that the CEL simulation was in good agreement with the model test. However, the CEL simulation could not present the characteristics the time-dependent added mass.
Using Artificial Intelligence Techniques in Modeling and Predicting the Rheological Behavior of Nano-Based Drilling Fluids
Authors: Gasser Moamen , Mahmoud Omar , Ibrahim Fatma , Abadir Magdi 
Published: October 2021

Abstract
Drilling process is one of the main operations in the extraction of hydrocarbons from petroleum reservoirs. It comes right after the exploration processes. Drilling fluids are necessary for controlling the wells and performing different functions during the drilling operation. They perform many roles in lifting the cuttings from the bottom of the well to the surface and cooling/lubricating the drill pipes and bit. Furthermore, they provide the desired hydrostatic pressure to overbalance pore pressure in addition to produce a thin/impermeable filter cake that can prevent or reduce the possible damage to the formations. It is mandatory to keep monitoring, enhancing, and optimizing the properties of the drilling fluids.
Recently, different additives, among which nanoparticles (NPs), have been investigated to improve, and maximize the benefits of the drilling fluids accordingly to meet the new challenges. The rheological behavior of such complex fluids has shown different enhancements up on the utilization of those additives. The rheological properties of the drilling fluids are accurately measured on the surface; however, the behavior of those properties may change with time and under harsh drilling conditions, such as high pressure/high temperature environments. For that, different models are introduced and used to predict and optimize the rheological characteristics of such fluids.
Bingham, Herschel-Bulkley, Power Law, Casson and others are commonly used as rheological models to predict the drilling fluid behavior. In the last decade, a new trend of developing new models and correlations using the artificial neural networks (ANN) have been introduced to the petroleum field. Mathematical formulas can be developed using ANN, which then can be used to predict the behavior of certain parameter(s) by knowing other ones. Using ANN have shown to be more reliable and accurate in predicting the rheological properties of the drilling fluids, such as apparent viscosity (AV), plastic viscosity (PV), yield point (YP), maximum shear stress, and change in the mud density at various conditions.
This work aims at using ANN technique to develop suitable models that can predict the rheological behavior of nano-based drilling fluids. The effect of NPs-type, -size, -concentration, and drilling fluid formulations will be considered, which may pave the road for new applications and efficient utilizations.
Hydrogen’s Peculiar Effect on Material Properties: Do We Need to Be Concerned About Hydrogen Transport in Pipelines?
Authors: Østby Erling , Hugaas Bjørn-Andreas , Horn Agnes Marie 
Published: October 2021

Abstract
Considering the vast number of articles that have been published during the last 150 years related to hydrogen embrittlement and the multiple attempts to explain the governing mechanisms, it is evident that hydrogen’s effect on mechanical properties in steel is still a controversial topic. This little atom has even by some authors been referred to as the “little devil”. We do not intend to explore this particular description of hydrogen any further. However, we would like to shed some light on the key technical aspects we believe need to be further scrutinized and understood to ensure that the decision-makers have sufficiently reliable data available to decide whether hydrogen gas can be safely transported in new or existing offshore pipelines at an acceptable cost.
Numerical Modeling of Sustainable Atmospheric Boundary Layer for Offshore Floaters
Authors: Kim Jang Whan , Jang Hyunchul , Yeon Seongmo , Kim Hyunjoe 
Published: October 2021

Abstract
Wind load is one of the major design load considerations for the hull and mooring of offshore floating facilities. The first step to minimize the uncertainties in wind load is generating an accurate wind profile that satisfies design requirements.
Recently, there was a joint-industry effort to develop CFD modeling practices on wind-load estimation in SNAME OC-8 CFD Task Force (OMAE2018-78699). The Task Force developed the modeling practice for the NPD (Norwegian Petroleum Directorate) model commonly used for offshore platform design, and several independent participants in the Task Force successfully validated the practice for a topsides of a semi-submersible platform. The sustainable wind profile was able to be generated within 1% tolerance of the target wind profile, and the calculated wind loads on the topsides from CFD simulations were close to the model test data with low uncertainty levels.
In the present study, the numerical modeling for the sustainable ABL is extended to other popular wind models such as the ESDU (Engineering Science Data Unit) and the power-law models. The study is a part of a joint-development project between TechnipFMC, Chevron, and Samsung Heavy Industries. The analytic or numerical formulae of wind speed and turbulent quantities for several RANS (Reynolds-Averaged Navier-Stokes) models are derived for the wind models, and the sustainability of wind profiles are verified.
Flow-Induced Vibration Screening of a Thermoplastic Composite Pipe Water Injection Jumper
Authors: Pontaza Juan P. , Nadathur Varadarajan , Rosche John L. 
Published: October 2021

Abstract
An active subsea field in the Gulf of Mexico has adopted a thermoplastic composite pipe (TCP) water injection jumper for its waterflood upgrade. The jumper assembly is composed of a TCP span attached to steel piping on either end. The TCP spool is lightweight and flexible relative to the traditional steel-only M-shaped subsea jumpers. As such, the flow-induced vibration (FIV) threat from internal fluid flow must be assessed for the intended service. A three-tiered approach is used to assess the level of FIV threat expected in this TCP subsea jumper application. A high-level screening based on widely used industry guidelines indicates a susceptibility to FIV fatigue failure for the steel piping in the TCP jumper assembly. A comprehensive screening based on structural finite element analysis and computational fluid dynamics shows that the vibration levels and stress cycling due to FIV will be acceptable for the intended water injection application and a 30-year design life, when adopting a factor of safety of 10 for subsea service. We evaluate the effect of doubling the length of the steel piping on either end of the TCP span, as a means to increase the overall span of the TCP jumper assembly. Lastly, we draw a comparison between a traditional all-steel M-shaped jumper and the TCP jumper in terms of FIV fatigue life, for the same operating conditions and the same total suspended span.
A CFD Research on the Effect of Pre-Swirl Stator Blades Number on a Pumpjet Propulsor
Authors: Guodong Wang , Jun Yang , Jiawei Yu , Wenjing Yang , Dakui Feng 
Published: October 2021

Abstract
In this paper, effect of different pre-swirl stator number on open water performance of a pumpjet propulsor was studied. The pumpjet propulsor consists of shaft system, pre-swirl stator, rotor and duct. The numerical simulations were based on HUST-Ship, a series of inhouse codes, solving the Reynolds Averaged Navier-Stokes (RANS) equation. The computational region was discretized by structured grids and SST k-ω turbulence equations was discretized by finite difference method. The performances of rotor, pre-swirl stator and duct were monitored separately in order to understand the effect in the thrust and the torque. It was found that with the increase of the number of pre-swirl stator blades, the thrust produced by rotor blades increased. However, the number of pre-swirl stator blades influences the thrust of stator, and may have negative effect on the total thrust. In the meantime, thrust of duct also has a little increase. With the increase of the number of pre-swirl stator blades, the propulsion efficiency increases first and then decreases.
A Frequency-Domain Screening Methodology for Flow-Induced Vibration in Piping
Authors: Pontaza Juan P. 
Published: October 2021

Abstract
A three-tiered approach is advocated to assess the level of flow-induced vibration (FIV) threat to process piping due to internal flow. The first-tier assessment is a high-level design check on the possibility of FIV. The tier-1 screening does not provide a framework for the direct estimation of vibration levels, stress, or fatigue damage. The third-tier assessment is termed a comprehensive screening and relies on computational fluid dynamics (CFD) to predict the flow-induced forcing, coupled to a structural finite element model to obtain the response of the piping (vibration levels and stresses), from which an estimate of fatigue damage at critical locations is computed. The tier-3 screening may be computationally intense (e.g., for multiphase flow) and is generally not fast to perform. This paper presents a second-tier assessment (intermediate between the tier-1 and tier-3 screenings), where the flow-induced loading is represented by power spectral density (PSD) curves, which are inputs to a structural finite element model of the piping. The structural finite element analysis (FEA) is performed in the frequency domain, implying fast turnaround time requiring short computing time. The FEA yields a prediction of vibration levels and dynamic stress, from which the sought-after estimates of fatigue damage are computed. The outcome of a tier-2 screening for vibrating piping in a metering skid is presented and the predictions compared against field measurements using accelerometer data (vibration levels) and strain gauge data (dynamic stress). A tier-2 screening is performed for a subsea water injection jumper and the results compared against those of a tier-3 screening.
A New Transient Thermal Model for Predicting Cooling Temperature and Cooldown Time of a Subsea Pipe-in-Pipe Flowline System Transporting Waxy Hydrocarbons
Authors: Shukla Keshawa 
Published: October 2021

Abstract
The proper understanding of cooling temperature and cooldown time for the operation of a subsea system producing hydrocarbons from the reservoir to the host facility is one of the important flow assurance issues for managing heat retention in the production system due to solids formation and their deposition. In this paper, an analytical transient thermal model is developed for determining the cooling temperature and cooldown time for shut-in operations of a subsea pipe-in-pipe production system, transporting waxy crude oil from the reservoir to the host facility. Here, the cooldown time is defined as the time when the fluid temperature approaches the wax appearance temperature before reaching the hydrate formation temperature during any shut-in operations. The analytical model builds upon an inhomogeneous transient method incorporating an internal temperature gradient. The model results are benchmarked against the commercial OLGA simulation results for a few selected deepwater pipe-in-pipe flowline configuration. The model predictions resemble well with OLGA results over a range of conditions. The analytical model could optimize dry insulation and cooldown time requirements efficiently for the assumed PIP flowline configurations and fluid properties under any subsea environments.
Fatigue Assessment on Reverse–Balanced Flange Connections In Offshore Floating Wind Turbine Towers
Authors: Zou Tao , Liu Wenjie , Li Mingxin , Tao Longbin 
Published: October 2021

Abstract
Offshore floating wind turbines (FWTs) in deep water experience cyclic loadings from both environment and mechanical operations. For FWTs, the upper turbine and tower are mainly subjected to wind loading; and the floater is subjected to wave forces. It has been widely accepted that there is a strong coupling between the floater motions and the turbine forces. As the tower is placed between the upper wind turbine and the floater, both wind and wave loadings affect the cyclic forces on the tower. The construction of towers makes use of prefabricated segments. These prefabricated segments are bolted together with flanges at either end. The paper aims to investigate the axial hotspot stress on FWT’s tower base and analyze its induced fatigue damage at the welding joints around the flanges. A coupled aero-hydro-servo-elastic analysis is conducted to simulate the motion of FWTs. Then, the local welding joint along the reverse-balanced flange connection is modeled to consider the influence of local geometry. At last, the hourly fatigue damages at four locations over the tower base section are compared.
Development of Methods for Temperature Calculation of LNG Carrier Hull
Authors: Islam MD Shafiqul , Choi Tae-Soon , An Tae-Hyun , Song Kang-Hyun 
Published: October 2021

Abstract
LNG carriers are vessels used to store and transport liquefied natural gas. LNG, in its liquid form has the temperature of minus 163 degrees Celsius. Therefore, the types of steel used to build the hull structure must withstand the impact of low temperatures. Cargo Containment System (CCS) is used to reduce the transfer of heat from the outside environment into the cargo tank and to keep the LNG in liquid state. Presently, the most popular types of CCS are designed by GTT (Gaztransport & Technigaz). However, Korean shipyards, KOGAS (Korea Gas Corporation) and many other companies around the world are developing their own CCS systems. The thermal analysis of LNG carrier hull is generally performed by the CCS developer and therefore, in order to assist the new CCS developers and LNG carrier designers, KR has developed a guideline for temperature calculation of Membrane type LNG carrier’s hull. This study is a part of the guidelines and focuses on numerical and analytical solution procedures for accurate hull temperature calculation. For verification and accuracy of these methods, temperature calculation of a Membrane type LNG carrier hull is carried out and the results are compared with each other. Both methods, thoroughly analyzed in this study, could be applied in the design of membrane type LNG carrier hulls.
Quality of life in elderly ICU survivors before the COVID-19 pandemic: a systematic review and meta-analysis of cohort studies
Authors: Ariyo Kevin , Canestrini Sergio , David Anthony S , Ruck Keene Alex , Wolfrum Sebastian , Owen Gareth 
Published: October 2021

ObjectivesThe influence of age on intensive care unit (ICU) decision-making is complex, and it is unclear if it is based on expected subjective or objective patient outcomes. To address recent concerns over age-based ICU decision-making, we explored patient-assessed quality of life (QoL) in ICU survivors before the COVID-19 pandemic.DesignA systematic review and meta-analysis of cohort studies published between January 2000 and April 2020, of elderly patients admitted to ICUs.Primary and secondary outcome measuresWe extracted data on self-reported QoL (EQ-5D composite score), demographic and clinical variables. Using a random-effect meta-analysis, we then compared QoL scores at follow-up to scores either before admission, age-matched population controls or younger ICU survivors. We conducted sensitivity analyses to study heterogeneity and bias and a qualitative synthesis of subscores.ResultsWe identified 2536 studies and included 22 for qualitative synthesis and 18 for meta-analysis (n=2326 elderly survivors). Elderly survivors’ QoL was significantly worse than younger ICU survivors, with a small-to-medium effect size (d=0.35 (−0.53 and −0.16)). Elderly survivors’ QoL was also significantly greater when measured slightly before ICU, compared with follow-up, with a small effect size (d=0.26 (−0.44 and −0.08)). Finally, their QoL was also marginally significantly worse than age-matched community controls, also with a small effect size (d=0.21 (−0.43 and 0.00)). Mortality rates and length of follow-up partly explained heterogeneity. Reductions in QoL seemed primarily due to physical health, rather than mental health items.ConclusionsThe results suggest that the proportionality of age as a determinant of ICU resource allocation should be kept under close review and that subjective QoL outcomes should inform person-centred decision -aking in elderly ICU patients.PROSPERO registration numberCRD42020181181.
FullFix: a randomised controlled trial of a telephone delivered transdiagnostic intervention for comorbid substance and mental health problems in young people
Authors: Walter Zoe , Quinn Catherine A , Dingle Genevieve , Pocuca Nina , Baker Amanda L , Beck Alison , De Andrade Dominique , Toombs Maree , Hides Leanne 
Published: October 2021

IntroductionTransdiagnostic cognitive–behavioural therapy (CBT) targets common psychological factors that underlie multiple disorders. While transdiagnostic interventions are a promising new approach, limited research has evaluated these treatments within the alcohol and other drug (AOD) sector for young people with comorbid mental health symptoms. This project will examine the feasibility and preliminary efficacy of FullFix—a new risk-targeted transdiagnostic CBT telehealth programme for comorbid AOD and depression/anxiety disorders in young people. Secondary aims are to identify moderators and mediators of treatment outcomes, to determine how and why treatment is effective and who is most likely to benefit.Methods/designParticipants will be 130 young people (aged 16–35) accessing AOD services in Queensland, Australia, with comorbid mental health symptoms. They will be randomised to receive either the FullFix intervention plus standard AOD care or standard AOD care alone. Primary outcomes on AOD use and mental health symptoms will be reassessed at 6 weeks, 3 months, 6 months and 12 months, along with secondary outcomes of emotion regulation, social connectedness, perceived self-efficacy, coping skills and quality of life. The trial commenced on October 2018 and expected completion date is September 2021.Ethics and disseminationEthical approval for this trial was provided by the University of Queensland (#2018001185). The results of the trial will be disseminated through publication in a peer-reviewed scientific journal, scientific presentations at conferences and distributed via a report and presentations to the partner organisation.Trial registration numberACTRN12618001563257.
Relationship between environmental factors and responsive behaviours in long-term care homes: a secondary data analysis
Authors: Holt Kelsey , Hoben Matthias , Weeks Lori , Estabrooks Carole 
Published: October 2021

ObjectiveResponsive behaviours (eg, wandering, resisting care and verbal abuse) are a continuing issue for staff and individuals living in long-term care (LTC) homes. The LTC environment can influence responsive behaviours and is a factor in determining the quality of life for those living there. The ways in which the quality of the environment might influence responsive behaviours has not been investigated yet. We hypothesised that better quality environments would be associated with reduced rates of responsive behaviours. We used a tool that simultaneously encompasses human and structural elements of the environment, a novel approach in this field of research.DesignCross-sectional study, using data collected from September 2014 to May 2015 as part of the Translating Research in Elder Care research programme.SettingA representative, stratified (size, owner-operator model and health region) random sample of 76 LTC homes in British Columbia, Alberta, Manitoba.Participants13 224 individuals (67.3% females) living in participating LTC homes.Outcome measuresQuality of care unit work environment was assessed using the observable indicators of quality (OIQ) tool. Responsive behaviours were assessed using routinely collected Resident Assessment Instrument-Minimum Data Set V.2.0 data.ResultsAdjusted regression coefficients of overall Aggressive Behaviour Scale score and interpersonal communication were 0.02 (95% CI −0.011 to 0.045), grooming 0.06 (95% CI −0.032 to 0.157), environment-basics 0.067 (95% CI 0.024 to 0.110), odour −0.066 (95% CI −0.137 to −0.004), care delivery −0.007 (95% CI −0.033 to 0.019), environment-access −0.027 (95% CI −0.062 to 0.007), environment-homelike −0.034 (95% CI −0.065 to −0.002) and total OIQ score 0.003 (95% CI −0.004 to 0.010).ConclusionsWe found small associations between the environmental quality and responsive behaviours in Western Canadian LTC homes. Higher scores on homelikeness were associated with decreased responsive behaviours. Higher scores on basic environmental quality were associated with increased responsive behaviours.