bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Cumulative Output Energy of Oscillating Water Column Wave Energy Converter Considering Power Take Off Damping
Authors: Iino Mitsumasa , Miyazaki Takeaki , Iida Makoto 
Published: December 2020

Abstract
The objective of this study is to investigate the influence of damping from the PTO device on the cumulative output of the oscillating water column wave energy converter under real sea conditions which encompasses wide range of wave period and height. In this presentation, a time domain dynamic simulation model of OWC motion is developed and validated with water tank test results. Then the model is used to calculate a wide range of wave period and height. Finally, annual cumulative air power output of OWC is calculated with different damping values.
In the water tank experiment, a cylindrical oscillating water column with a diameter of 0.3 m and submerged depth of 0.2 m is tested. PTO damping was emulated by using several orifice plates. Since the orifice pressure is proportional to square of flow-rate of the orifice, In the simulation, a model was constructed to solve the dynamic equation of motion assuming water column as a rigid equivalent floating body. Validation showed the model captures the influence of PTO damping as observed in the water tank testing. Using simulation, output air power from real scale OWC was evaluated under wide range of inlet wave period and height. With the output power database from dynamic simulation and frequency of wave height and period at specific sites in Japan (Fukui and Kamaishi), annual cumulative output power is calculated.
From the results, it was confirmed that a higher output can be obtained with higher energy in high waves by adopting a damping characteristic that increases the efficiency under a wide wave condition rather than a nozzle characteristic that achieves maximum efficiency in the resonance period. Furthermore, it became clear that the damping that increases the maximum efficiency does not necessarily increase the accumulated energy. When considering operation in real sea condition in the future, it is not always effective to select PTO damping that maximizes the output at specific wave height or period. And it is important to adopt a method that can estimate wide range of wave condition and evaluate the cumulative output power.
Statistical Determination of Bit-Rock Interaction and Drill String Mechanics for Automatic Drilling Optimization
Authors: Ambrus Adrian , Daireaux Benoît , Carlsen Liv A. , Mihai Rodica G. , Karimi Balov Mohsen , Bergerud Ronny 
Published: December 2020

Abstract
The ability to predict the response of a drill bit to the topside axial and rotational velocities of the drill-string is a prerequisite for any system aimed at automatically controlling the drilling parameters to optimize the rate of penetration and the overall quality of the well construction process. When drilling with a Polycrystalline Diamond Compact (PDC) bit, even the steady-state response can exhibit complex behavior, characterized by the presence of (at least) three different regimes whose range and parameters depend upon the bit characteristics and the mechanical properties of the formations being drilled. Transient effects significantly complicate the situation, especially when vibrations (axial, rotational or lateral) disturb the drilling process. Often, the root cause of these vibrations lies in the bit-rock interaction itself, while the drill string, through its elasticity and interaction with the borehole wall, may amplify or attenuate these vibrations. Therefore, continuous calibration of the drill string and bit-rock parameters from available surface and downhole measurements is critical for any automated control system relying on dynamic models of the drilling process.
We present a calibration procedure whose goal is two-fold: first, to identify the time-varying parameters involved in the bit-rock interaction, and second, to provide a low-order, transfer function model approximation of the drill string axial and rotational dynamics. Our approach is based on particle filter techniques and a refined instrumental variable method for transfer function model estimation, and allows for real-time estimation of the various model parameters. We illustrate its behavior against recorded drilling data, where the proposed methods are shown to capture the different dynamics in place. We explain, in addition, how the calibrated drill string and bit-rock interaction models can be integrated in a framework to identify drilling parameter regions prone to axial or rotational vibrations.
Collapse Analysis of Ship Hull Girder Using Hydro-Elastoplastic Beam Model: Part 2
Authors: Ko Han Htoo Htoo , Tatsumi Akira , Iijima Kazuhiro , Fujikubo Masahiko 
Published: December 2020

Abstract
In Part 1 study, a time-domain collapse analysis method of ship hull girder was developed and named FE-Smith method. Hull girder was treated as elastoplastic beam model and Smith’s method was used for collapse analysis of cross sections. A concept of average stress-average plastic strain relationship was introduced so that nonlinear collapse behavior of members can be treated as pseudo strain-hardening/softening behavior. Fluid-structure interaction effects were considered. Uniform cross-section beam was assumed as a most fundamental study.
In this Part 2, a container ship is taken as subject model. Not only FE-Smith analysis but also non-linear FE analyses using shell model for collapse parts are performed for comparison purpose. Two types of average stress-average strain curves are considered for FE-Smith analysis, i.e. obtained by Gordo-Soares formulae and by shell FEM. Applicability of FE-Smith method is examined comparing with more precise but time-consuming methods. Some parametric studies are also performed. Wave response will be reported in the next papers.
Subsea HIPPS Monetary Value: Perception and Reality
Authors: Priyadarshi Hemant , Harrold David , Baig Arif , Tagore Anupam 
Published: December 2020

Abstract
In a subsea production environment, a HIPPS (High Integrity Pressure Protection System) is used to operate the system at a design pressure lower than the Shut-in tubing pressure. It helps maintain high reliability against overpressure or burst scenarios. This paper introduces a subsea HIPPS system and its application principle. It also discusses how HIPPS can be an enabler for developing high pressure remote or stranded fields.
Furthermore, it discusses the perceived hardware/project cost reduction benefits, which may or may not be available or are insignificant. From experience on multiple field development projects, HIPPS is an enabler for connecting differently rated systems; however, monetary savings are not a given and vary from field to field. Attention must be given to total installed costs of the system before associating monetary gains with the introduction of HIPPS. The content and scenarios presented in this paper pertain to deep-water field developments.
Development of a Numerical Dynamic Mooring Model for Visco-Elastic and Visco-Plastic Deformation of Synthetic Ropes
Authors: Nguyen Nhu , Sharman Krish Thiagarajan 
Published: December 2020

Abstract
Synthetic ropes are increasingly being considered for various offshore and marine applications, including for mooring offshore wind turbines and for aquaculture cages. Studies have shown that nonlinear behaviors of a synthetic rope in a dynamic environment can complicate the mooring system analysis. Nonlinear stiffness coupled with time- and load history-dependent characteristics of fibrous materials can allow for over or under estimation of the mooring forces. It is critical that these nonlinear properties are incorporated correctly into a mooring model, especially for studies of structures’ performances in extreme events. The study aims at developing a simulation tool capable of predicting the dynamic behavior of highly extensible synthetic mooring system used in coastal and offshore floating structures. The program employs an implicit finite-difference approach to model the dynamic behaviors of the mooring line subjected to user-defined motions of the fairlead. As opposed to a linear stress-strain relationship typically incorporated in other mooring models, the current program is built with constitutive model of fibrous materials to account for the nonlinearity time- and load-dependent characteristics of synthetic lines. As part of the program, an inverted constitutive stress-strain model, in which stresses are calculated from given strains in stress-based formulas, were presented. Comparisons with published data indicates that the proposed inverted nonlinear stress-strain formulas were successfully integrated with the mooring solver. The coupled nonlinear mooring program predicts accurately both nonlinear reversible and irreversible deformations of synthetic cables.
Comparison of the CFD Results to PIV Measurements in Kinematics of Spilling and Plunging Breakers
Authors: Düz Bülent , Scharnke Jule , Hallmann Rink , Tukker Jan , Khurana Siddhant , Blanchard Kevin 
Published: December 2020

Abstract
The kinematics under spilling and plunging breakers are investigated using both experimental and numerical methods. In a modular laboratory flume, the breakers were generated using dispersive focusing, and the kinematics underneath them were measured utilizing the Particle Image Velocimetry (PIV) technique. Using the state-of-art high-speed video cameras and lasers, the kinematics were measured at a high sampling rate without needing phase-locked averaging. Afterwards, Computational Fluid Dynamics (CFD) simulations were carried out for comparison purposes. These simulations were run in single-phase using a finite-volume based Navier-Stokes solver with a piecewise-linear interface reconstruction scheme. The spilling and plunging breakers from the measurements were reconstructed in the computational domain using an iterative scheme. As a result a good match with the measured waves was obtained in the simulations. Results indicate that even though measured kinematics are somewhat higher than the simulated ones especially in the spilling and overturning regions, the CFD simulations can accurately capture the relevant details of the flow and produce reasonably accurate kinematics in comparison with the PIV results.
Hydrodynamic Analysis of Macroalgae Local Model Using Computational Fluid Dynamics
Authors: Chen Ming , Yim Solomon C. , Cox Daniel , Yang Zhaoqing , Mumford Thomas 
Published: December 2020

Abstract
In this article, a local scale, fully nonlinear coupled fluid-structural interaction (FSI) sugar kelp model has been developed using a computational fluid dynamics (CFD) method. In this model, to be consistent with available experimental data, the sugar kelp is approximated as elongated rectangles with smoothed isosceles triangles at the ends and a single kelp model with one end fixed in a channel with constant current model is developed. Several different current speeds are simulated, and the resulting drag forces and calculated drag coefficients are validated by comparison with experimental data from the literature. In a previous study, a global scale model was developed using a computational structural dynamics (CSD) method to simulate macroalgae farming system and guide the system configuration design. In the global scale model, the hydrodynamic forces are calculated using Morison’s equation and the kinematics and dynamics of the sugar kelp are simplified and the group of kelps attached to the long line is modeled as a slender structure with the same length and an effective diameter such that the volumes are consistent with the real physical system. This simplified model matches the weight and buoyancy but adjusting the hydrodynamic properties when the general hydrodynamic coefficients are employed. Therefore, optimal hydrodynamic coefficients used in global scale model were determined to obtain the hydrodynamic force more accurately. The validated local scale model is then be applied to determine the hydrodynamic coefficients of the simplified sugar kelp model for global dynamic analysis.
Centrifuge Model Tests on Effects of Spudcan Penetration on Adjacent Loaded Piles
Authors: Wang Jianhua , Fan Yifei 
Published: December 2020

Abstract
It is very important for designers of offshore platforms to understand affecting mechanism of mobile jack-up spudcan penetration and extraction on adjacent loaded piles. Existing centrifuge model tests are on effects of spudcan penetration on adjacent unloaded piles. In engineering, offshore platform piles are subjected to lateral and vertical pile head loads before spudcan penetration. In order to understand affecting mechanism of spudcan penetration on adjacent loaded piles, centrifuge model tests were conducted under 50g condition. Model test strata are the saturated soft clay and the fine sand and the model pile head constraint is free. Spudcan penetration resistances, lateral earth pressures along pile shaft, lateral pile deflection, vertical pile displacement, bending moments and axial forces along pile shaft are measured during spudcan penetration and after extraction. Effects of spudcan penetration on the pile-soil interaction p-y relationship and the bearing capacity of piles are analyzed based on model test results. Results show that the lateral soil resistance affected by spudcan penetration decreases due to soil movement. The lateral deflection of loaded pile obviously increases, the side frictional resistance decreases and the end resistance increases during spudcan penetration. The spudcan penetration-induced incremental pile response does not disappear after spudcan extraction. These results are helpful for understanding the effect mechanism of spudcan penetration and extraction on adjacent loaded piles.
Numerical Modeling of Turbulent Wall-Bounded Oscillatory Flow and its Effect on Small-Diameter Pipelines
Authors: Jiang Hongyi , Cheng Liang 
Published: December 2020

Abstract
This study investigates the effect of wave-induced boundary layer on the on-bottom stability of small-diameter pipelines laid on the seabed. An ω-based wall boundary condition is adopted, owing to its high mesh resolution down to the viscous sublayer to resolve the flow around the pipeline. By taking into account the wave boundary layer, the present numerical simulations predict required specific gravity for small-diameter pipelines close to the theoretical estimation by Cheng et al. (2016) and, as expected, much smaller than those recommended by DNV-RP-F109.
Roll Damping Simulations of an Offshore Heavy Lift DP3 Installation Vessel Using the CFD Toolbox OpenFOAM
Authors: Devolder Brecht , Stempinski Florian , Mol Arjan , Rauwoens Pieter 
Published: December 2020

Abstract
In this work, the roll damping behavior of the offshore heavy lift DP3 installation vessel Orion from the DEME group is studied. Boundary element codes using potential flow theory require a roll damping coefficient to account for viscous effects. In this work, the roll damping coefficient is calculated using the Computational Fluid Dynamics (CFD) toolbox OpenFOAM. The two-phase Navier-Stokes fluid solver is coupled with a motion solver using a partitioned fluid-structure interaction algorithm. The roll damping is assessed by the Harmonic Excited Roll Motion (HERM) technique. An oscillating external moment is applied on the hull and the roll motion is tracked. Various amplitudes and frequencies of the external moment and different forward speeds, are numerically simulated. These high-fidelity full-scale simulations result in better estimations of roll damping coefficients for various conditions in order to enhance the accuracy of efficient boundary element codes for wave-current-structure interactions simulations.
Dynamic Response of Jacket-Support Offshore Wind Turbine Under Ice Crushing Load
Authors: Chuang Zhenju , Li Chunzheng , Liu Shewen , Lu Yu 
Published: December 2020

Abstract
Offshore wind is one of the fastest developing renewable energy in the world. With increasing exploratory activities in the polar area, wind energy in the cold climate attracts more and more attention. This paper presents an integrated analysis of the ice-structure interaction of a jacket-type offshore wind turbine (OWT). An aero-hydro-servo-elastic jacket wind turbine is created in FAST, which is a well-known tool for wind turbine simulation. Due to vertically sided jacket legs, crushing ice-structure interaction modes are calculated based on the methodology suggested by ISO 19906. Time-domain calculations are carried out for random crushing, intermittent crushing and lock-in crushing between the bottom fixed wind turbine and moving ice feature. Influential parameters like ice thickness, ice strength, ice moving direction and velocity are all studied in this paper. Results show that the ice load has a significant impact on the structure response. The more ice thickness and ice strength will induce the higher structure response mean level, as well as the oscillation amplitudes in all the investigated crushing modes.
MoorDyn V2: New Capabilities in Mooring System Components and Load Cases
Authors: Hall Matthew 
Published: December 2020

Abstract
MoorDyn, an open-source mooring dynamics model, is being expanded with capabilities for additional mooring system features and load cases. As floating wind turbine technology matures, mooring systems are becoming more sophisticated and more complex scenarios need to be considered in the design process. Mooring systems may have synthetic line materials, ballast/buoyancy bodies along the lines, or interconnections between platforms. Failure modes may involve multiple cascading line failures that depend on mooring system dynamics.
Features recently added to MoorDyn aim to address these emerging needs. MoorDyn’s linear elasticity model has been supplemented to support user-defined stress-strain curves, which can be adjusted to represent synthetic mooring materials. Rigid six-degree-of-freedom bodies in the mooring system can now be modeled using two new model objects. “Rod” objects provide an option for rigid cylindrical bodies. They use the existing Morison equation-based hydrodynamics model and can be connected to mooring lines at either end. “Body” objects provide a generic six-degree-of-freedom rigid-body representation based on a lumped-parameter model of translational and rotational properties. Rod objects can be added to Body objects and mooring lines can be attached at any location, allowing a wide variety of submerged structures to be integrated into the mooring system. Lastly, a means of dynamically simulating mooring line failures has been implemented.
These new features, currently in the C++ version of MoorDyn, are described and then demonstrated on a two-turbine shared-mooring array. A qualitative view of the results suggests the new features are functioning as expected.
Growth during the first summer at sea modulates sex-specific maturation schedule in Atlantic salmon
Authors: Tréhin Cécile , Rivot Etienne , Lamireau Ludivine , Meslier Lisa , Besnard Anne-Laure , Gregory Stephen D. , Nevoux Marie 
Published: December 2020

Recent decline in abundance of Atlantic salmon (Salmo salar) and concomitant changes in life history may result from a decline in the growth conditions during marine migration. Available literature suggests the existence of a sex-specific reaction norm linking maturation with environmental growth conditions at sea. However, the extent to which this mechanism explains variations in age at maturity remains unclear. Using a historical collection of scales (1987–2017) from the Sélune River, France, we showed that marine growth declined over the first summer and remained stable during the subsequent periods at sea among returning salmon. Results support the hypothesis of a sex-specific probabilistic reaction norm, with individual probability to return after 1 year at sea increasing when growth increases. Females may require higher growth than males to attain their maturation threshold. This mechanism is a good candidate to explain temporal variability in sea-age at return at both the individual and population level in the Sélune population and in many other southern European populations.
Searching for lepton flavor violating decays $$\tau \rightarrow Pl$$ in the minimal R-symmetric supersymmetric standard model
Authors: Sun Ke-Sheng , Guo Tao , Li Wei , Yang Xiu-Yi , Zhao Shu-Min 
Published: December 2020

AbstractWe analyze the lepton flavor violating decays $$\tau \rightarrow Pl$$

τ
→
P
l

($$P=\pi ,\eta ,\eta ';\;l=e,\mu $$

P
=
π
,
η
,

η
′

;

l
=
e
,
μ

) in the scenario of the minimal R-symmetric supersymmetric standard model. The prediction on the branching ratios BR$$(\tau \rightarrow P e)$$

(
τ
→
P
e
)

and BR$$(\tau \rightarrow P \mu )$$

(
τ
→
P
μ
)

is affected by the mass insertion parameters $$\delta ^{13}$$

δ
13

and $$\delta ^{23}$$

δ
23

, respectively. These parameters are constrained by the experimental bounds on the branching ratios BR($$\tau \rightarrow e (\mu ) \gamma $$

τ
→
e
(
μ
)
γ

) and BR($$\tau \rightarrow 3e(\mu )$$

τ
→
3
e
(
μ
)

). The result shows Z penguin dominates the prediction on BR($$\tau \rightarrow Pl$$

τ
→
P
l

) in a large region of the parameter space. The branching ratios for BR($$\tau \rightarrow Pl$$

τ
→
P
l

) are predicted to be, at least, five orders of magnitude smaller than present experimental bounds and three orders of magnitude smaller than future experimental sensitivities.
Evaluation of CCD cameras for beam profile monitoring with high intensity particle beams traversing gases
Authors: Hampf Raphael , Ulrich Andreas , Wieser Jochen 
Published: December 2020

AbstractMeasurements of the absolute sensitivity of three different optical cameras are presented. An absolutely calibrated tungsten strip-lamp was used for calibrating the devices. An experimental method for determining the solid angle which is accepted by the combination of the cameras with a broadband apochromatic lens is described. The results with five bandpass filters between 337nm and 740nm are shown. The signal to noise ratio and the spatial resolution of the camera systems is also discussed.
Optical properties of He+-implanted fused silica glass waveguides
Authors: You Jia-Li , Lin Shuo-Qi , Zhang Jie , Lin She-Bao , Fu Li-Li , Zheng Rui-Lin , Zhang Liao-Lin , Liu Chun-Xiao 
Published: December 2020

An optical waveguide is an important dielectric device that guides the propagation of light waves. Ion implantation is a competitive waveguide preparation technique with advantages including reliance, simpleness and flexibility. In this work, a 400-keV helium ion implantation with a fluence of [Formula: see text] ions/cm2 was carried out to manufacture a planar waveguide on the surface of the fused silica glass. The formation mechanism of the waveguide was analyzed by the nuclear energy deposition based on the SRIM 2013 and the refractive index distribution with the help of the reflectivity calculation method (RCM). The geometry structure and the guiding performance of the waveguide were studied by the metallographic microscope and the end-face coupling system, respectively. The investigation on the fabrication and characteristics of fused silica glass optical waveguides is of great significance for the development of passive devices in the field of optical communications.