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Interaction of turbulences with non-breaking divergent waves in an open channel Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2021-01-18 Ayoung Hwang; Woochan Seok; Sang Bong Lee
This paper presents a direct numerical simulation of turbulent flows over a bump in an open channel to examine the turbulence characteristics near divergent waves emanating from the bump and to investigate the interaction of the turbulences with the divergent waves. To verify the reliability of the simulations, the mean velocity profile and root-mean-square of velocity fluctuations are compared with
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Experimental investigation of towing- and course-stability of a FPSO towed by a tug-boat with lateral motion Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2021-01-16 Seung Hyeon Park; Seung Jae Lee; Sungwook Lee
In the conventional experiment to assess the towing operations, the towing stability of the towed vessel has been evaluated under the condition without lateral motion of the tug-boat. However, the tug-boats may have a lateral force to change the direction of the towed vessel. In this study, experiments have been conducted considering unsteady conditions in the towing system. First, a towing test system
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Comparative study on the prediction of speed-power-rpm of the KVLCC2 in regular head waves using model tests Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2021-01-16 Jin-Won Yu; Cheol-Min Lee; Jin-Hyeok Seo; Ho Hwan Chun; Jung-Eun Choi; Inwon Lee
This paper predicts the speed-power-rpm relationship in regular head waves using various indirect methods: load variation, direct powering, resistance and thrust identity, torque and revolution, thrust and revolution, and Taylor expansion methods. The subject ship is KVLCC2. The wave conditions are the regular head waves of λ/LPP = 0.6 and 1.0 with three wave steepness ratios at three ship speeds of
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Performance of a hydrofoil operating close to a free surface over a range of angles of attack Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2021-01-13 Zao Ni; Manhar Dhanak; Tsung-chow Su
Performance of a NACA 634-021 hydrofoil in motion under and in close proximity of a free surface for a large range of angles of attack is studied. Lift and drag coefficients of the hydrofoil at different submergence depths are investigated both numerically and experimentally, for 0° ≤ AoA≤30° at a Reynolds number of 105. The results of the numerical study are in good agreement with the experimental
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Validation of underwater explosion response analysis for airbag inflator using a fluid-structure interaction algorithm Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-12-25 Sang-Gab Lee; Jae-Seok Lee; Hyun Chung; Yangsup Na; Kyung-Hoon Park
Air gun shock systems are commonly used as alternative explosion energy sources for underwater explosion (UNDEX) shock tests owing to their low cost and environmental impact. The airbag inflator of automotive airbag systems is also very useful to generate extremely rapid underwater gas release in lab-scale tests. To overcome the restrictions on the very small computational time step owing to the very
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An investigation on the effect of the wall treatments in RANS simulations of model and full-scale marine propeller flows Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-12-24 Jung-Kyu Choi; Hyoung-Tae Kim
A numerical analysis is carried out for the marine propellers in open water conditions to investigate the effect of the wall treatments in model and full scale. The standard wall function to apply the low of the wall and the two layer zonal model to calculate the whole boundary layer for a transition phenomenon are used with one turbulence model. To determine an appropriate distance of the first grid
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Research on total resistance of ice-going ship for different floe ice distributions based on virtual mass method Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-12-22 Wei Guo; Qiao-sheng Zhao; Yu-kui Tian; Wan-chao Zhang
This paper presents the virtual mass method to implement the prediction of total resistance for ice-going ship in floe ice region based on the combined method of CFD and DEM. Two ways of floe ice distribution are adopted for the analysis and comparison. The synthetic ice model test has been conducted to determine the optimal virtual mass coefficients for the two different floe ice distributions. Moreover
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Control system design for vessel towing system by activating rudders of the towed vessel Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-12-14 Dong-Hun Lee; Soumayya Chakir; Young-Bok Kim; Duc-Quan Tran
In this study, the motion control problem of the vessel towed by a towing ship (tugboat) is considered. The non-powered towed ship is dragged by the towing ship. Even though the towed ship is equipped with propulsion systems, they cannot be used at low or constant speeds due to safety issues. In narrow canals, rivers, and busy harbor areas especially, where extreme tension is required during towing
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Numerical investigation of the unsteady flow of a hybrid CRP pod propulsion system at behind-hull condition Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-28 Yuxin Zhang; Xuankai Cheng; Liang Feng
Flows induced by hybrid CRP pod propulsion systems (CRP-POD) are fundamentally characterized by unsteadiness. This work presents a numerical study on the unsteady flow of a CRP-POD at behind-hull condition based on CFD (Computational Fluid Dynamics). Unsteady RANS method is adopted, coupled with SST k-ω turbulence model and sliding mesh method. The propeller thrusts and torques obtained by CFD is validated
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Numerical investigation on pressure responsiveness properties of the skirt-cushion system of an air cushion vehicle Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-29 Shengjie Xu; Yujia Tang; Kejie Chen; Zongke Zhang; Tao Ma; Wenyong Tang
The pressure responsiveness property of a skirt-cushion system, which is closely related to the overall performance of Air Cushion Vehicles (ACVs), has always been the difficulty and challenging problem involving cushion aerodynamics and flexible skirt dynamics. Based on a widely used bag and finger skirt-cushion system, the pressure responsiveness properties are investigated numerically. The physical
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Application of reinforcement learning to fire suppression system of an autonomous ship in irregular waves Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-24 Eun-Joo Lee; Won-Sun Ruy; Jeonghwa Seo
In fire suppression, continuous delivery of water or foam to the fire source is essential. The present study concerns fire suppression in a ship under sea condition, by introducing reinforcement learning technique to aiming of fire extinguishing nozzle, which works in a ship compartment with six degrees of freedom movement by irregular waves. The physical modeling of the water jet and compartment motion
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Overall hull girder nonlinear strength monitoring based on inclinometer sensor data Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-19 Gökhan Tansel Tayyar
It is announced a new procedure for the real-time overall hull response monitoring system depends on inclinometer sensor data. The procedure requires a few inclinometer sensors’ data, located on the deck. Sensor data is used to obtain curvature values; and curvature values are used to find out displacements or relevant moment values according to pre-calculated moment-curvature diagrams. Numerical studies
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A numerical study on hydrodynamic maneuvering derivatives for heave-pitch coupling motion of a ray-type underwater glider Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-16 Sungook Lee; Hyeung-Sik Choi; Joon-Young Kim; Kwang-Jun Paik
We used a numerical method to estimate the hydrodynamic maneuvering derivatives for the heave-pitch coupling motion of an underwater glider. It is very important to assess the hydrodynamic maneuvering characteristics of a specific hull form of an underwater glider in the initial design stages. Although model tests are the best way to obtain the derivatives, numerical methods such as the Reynolds-averaged
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Hull form design for resistance minimization of small-scale LNG bunkering vessels using numerical simulation Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-11 Kyung-Ryeong Pak; Gi-Su Song; Hee-Jung Kim; Hye-Jong Son; Hyoung-Gil Park
This paper aims to provide the most useful method of determining an optimum LCB position and design direction of fore- and aft-body hull shape for a SLBV. It is known that the SLBV has a lower length-to-beam ratio, larger Cb and simpler stern shape designed for the installation of azimuth thrusters comparing to those of conventional LNG carriers. Due to these specific particulars of SLBV, the optimum
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Low-cycle fatigue evaluation for girth-welded pipes based on the structural strain method considering cyclic material behavior Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-11 Jin-Ho Lee; Pingsha Dong; Myung-Hyun Kim
One of the main concerns in the structural integrity of offshore pipelines is mechanical damage from external loads. Pipelines are exposed to fatigue failure in welded joints due to geometric discontinuity. In addition, fatigue loads such as currents, waves, and platform motions may cause significant plastic deformation and fracture or leakage within a relatively low-cycle regime. The 2007 ASME Div
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Recent developments in remote inspections of ship structures Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-11 Laura Poggi; Tomaso Gaggero; Marco Gaiotti; Enrico Ravina; Cesare Mario Rizzo
In recent years robotics has become an important resource in engineering. Adoption of Robotics and Autonomous Systems (RAS) in activities related to ship inspections has obvious potential advantages, but also arises particular challenges, both from technical and legal viewpoints. The ROBINS project (ROBotics technology for INspection of Ships) is a collaborative project co-funded within the H2020 EU
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Maneuvering simulation of an X-plane submarine using computational fluid dynamics Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-04 Yong Jae Cho; Woochan Seok; Ki-Hyeon Cheon; Shin Hyung Rhee
X-plane submarines show better maneuverability as they have much longer span of control plane than that of cross plane submarines. In this study, captive model tests were conducted to evaluate the maneuverability of an X-plane submarine using Computational Fluid Dynamics (CFD) and a mathematical maneuvering model. For CFD analysis, SNUFOAM, CFD software specialized in naval hydrodynamics based on the
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Spatial target path following and coordinated control of multiple UUVs Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-11-03 Xue Qi; Peng Xiang; Zhi-jun Cai
The coordination control of multiple Underactuated Underwater Vehicles (UUVs) moving in three dimensional space is investigated in this paper. The coordinated path following control task is decomposed into two sub tasks, that is, path following control and coordination control. In the spatial curve path following control task, path following error dynamics is build in the Serret-Frenet coordinate frame
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Distributed plasticity approach for the nonlinear structural assessment of offshore wind turbine Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-19 Thanh-Tuan Tran; Mosaruf Hussan; Dookie Kim; Phu-Cuong Nguyen
This study provides an insight of the nonlinear behavior of the Offshore Wind Turbine (OWT) structure using the distributed plasticity approach. The fiber section beam-column element is applied to construct the finite element model. The accuracy of the proposed model is verified using linear analysis via the comparison of the dynamic characteristics. For collapse risk assessment of OWT, the nonlinear
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Development of a novel fatigue damage model for Gaussian wide band stress responses using numerical approximation methods Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-19 Seock-Hee Jun; Jun-Bum Park
A significant development has been made on a new fatigue damage model applicable to Gaussian wide band stress response spectra using numerical approximation methods such as data processing, time simulation, and regression analysis. So far, most of the alternative approximate models provide slightly underestimated or overestimated damage results compared with the rain-flow counting distribution. A more
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Motion predictive control for DPS using predicted drifted ship position based on deep learning and replay buffer Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-19 Daesoo Lee; Seung Jae Lee
Typically, a Dynamic Positioning System (DPS) uses a PID feed-back system, and it often adopts a wind feed-forward system because of its easier implementation than a feed-forward system based on current or wave. But, because a ship’s drifting motion is caused by wind, current, and wave drift loads, all three environmental loads should be considered. In this study, a motion predictive control for the
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Numerical study on supercavitating flow in free stream with regular waves Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-19 Da Li; Xujian Lyu
In this study, the supercavitating flow of a high-velocity moving body near air-water surface is calculated and analyzed based on a commercial CFD software ANSYS Fluent. The effect of regular wave parameters including both wave height and wavelength on the cavitating flow and force characteristics of a body at different velocities is investigated. It is found that the cavity shape, lift coefficient
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Numerical wind load estimation of offshore floating structures through sustainable maritime atmospheric boundary layer Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-27 Seong Mo Yeon; Joo-Sung Kim; Hyun Joe Kim
Wind load is one of the major design loads for the hull and mooring of offshore floating structures, especially due to much larger windage area above water than under water. By virtue of extreme design philosophy, fully turbulent flow assumption can be justified and the hydrodynamic characteristics of the flow remain almost constant which implies the wind load is less sensitive to the Reynolds number
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Experimental and numerical study on the wave force calculation of a partially immersed horizontal cylindrical float Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-16 Bijin Liu; Danjuan Fu; Youquan Zhang; Xiaoyun Chen
Taking the cylindrical float of the floating fence of a floating litter collection device as the research object, based on the shallow immersion characteristics of the cylindrical float, the Morison equation is modified, and the interaction between regular waves and the partially immersed horizontal cylindrical float is discussed in combination with scale model test. The results show that the modified
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Prediction of a transverse shrinkage of butt welded joints in shipyard conditions using the design of experimental approach Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-17 Tomasz Urbański; Maciej Taczała
This paper presents the results of research on transverse shrinkage of welded butt joints conducted according to the principles of experimental design and under production conditions for two main welding techniques used in shipbuilding (FCAW and SAW). Analysis took into account the technological and structural parameters influencing the assembly suitability of a large steel structure. The presented
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An optimization framework of a parametric Octabuoy semi-submersible design Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-09 Zhitian Xie; Jeffrey Falzarano
An optimization framework using genetic algorithms has been developed towards an automated parametric optimization of the Octabuoy semi-submersible design. Compared with deep draft production units, the design of the shallow draught Octabuoy semi-submersible provides a floating system with improved motion characteristics, being less susceptible to vortex induced motions in loop currents. The relatively
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Reaction force of ship stern bearing in hull large deformation based on stochastic theory Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-10-10 Sheng-dong Zhang; Zhi-lin Long; Xiu-ying Yang
A theoretical calculation model for ship stern bearings with large hull deformation is established and validated theoretically and experimentally. A hull simulation model is established to calculate hull deformations corresponding to the reaction force of stern bearings under multi-factor and multi-operating conditions. The results show that in the condition of wave load, hull deformation shows randomness;
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A parametric study on effects of pitting corrosion on stiffened panels’ ultimate strength Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-09-12 Liang Feng, Luocun Hu, Xuguang Chen, Hongda Shi
Pitting corrosion commonly shaped in hull structure due to marine corrosive environment seriously causes the deterioration of structural performance. This paper deals with the ultimate strength behaviors of stiffened ship panels damaged by the pits subjected to uniaxial compression. A series of no-linear finite element analyses are carried out for three stiffened panels using ABAQUS software. Influences
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An experimental study on the stern bottom pressure distribution of a high-speed planing vessel with and without interceptors Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-09-11 Woochan Seok, Sae Yong Park, Shin Hyung Rhee
In this study, the effects of hydrodynamic interceptors on a high-speed vessel were investigated to identify the operating principle based on experiments. Model tests were performed using a high-speed towing carriage. The resistance, trim and rise of Center of Gravity (CG) of the high-speed vessel were measured for various ship speeds and interceptor heights. As the interceptor height increased, the
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A hybrid algorithm of underwater structure vibration and acoustic radiation-propagation in ocean acoustic channel Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-09-10 Jia-xi Duan, Lin Zhang, Liang-long Da, Xue-hai Sun, Wen-jing Chen
In ocean environment, the sound speed gradient of seawater has an important influence on far field sound propagation. The FEM/BEM is used to decouple the vibroacoustic radiation of the spherical shell, and the Green function of the virtual source chain is adopted for decoupling. For far field radiated Sound Pressure Level (SPL), the Beam Displacement Ray normal Mode (BDRM) is employed. The vibration
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Study on sloshing simulation in the independent tank for an ice-breaking LNG carrier Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-09-10 Shifeng Ding, Gang Wang, Qiuming Luo
As the LNG carrier operates in ice covered waters, it is key to ensure the overall safety, which is related to the coupling effect of ice-breaking process and internal liquid sloshing. This paper focuses on the sloshing simulation of the ice-breaking LNG carrier, and the numerical method is proposed using Circumferential Crack Method (CCM) and Volume of Vluid (VOF) with two main key factors (velocity
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An advanced technique to predict time-dependent corrosion damage of onshore, offshore, nearshore and ship structures: Part II = Application to the ship’s ballast tank Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-24 Do Kyun Kim, Hui Ling Lim, Nak-Kyun Cho
In this study (Part II), the empirical formulation of corrosion model of a ship’s ballast tank was developed to predict nonlinear time-dependent corrosion wastage based on the advanced data processing technique proposed by Part I. The detail on how to propose generalised mathematical formulation of corrosion model was precisely documented in the previous paper (Part I). The statistical scatter of corrosion
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An advanced technique to predict time-dependent corrosion damage of onshore, offshore, nearshore and ship structures: Part I = generalisation Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-24 Do Kyun Kim, Eileen Wee Chin Wong, Nak-Kyun Cho
A reliable and cost-effective technique for the development of corrosion damage model is introduced to predict nonlinear time-dependent corrosion wastage of steel structures. A detailed explanation on how to propose a generalised mathematical formulation of the corrosion model is investigated in this paper (Part I), and verification and application of the developed method are covered in the following
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Simulation of greenhouse gas emissions of small ships considering operating conditions for environmental performance evaluation Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-08 Sookhyun Jeong, Jong Hun Woo, Daekyun Oh
This study developed a method for simulating greenhouse gas (GHG) emissions considering changes in conditions that may occur during the actual operation of small ships. Additionally, we analyzed and compared the results of the proposed method with that of existing emission simulations according to life-cycle assessment (LCA), thus verifying the proposed method’s effectiveness. Through the results of
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Robust design on the arrangement of a sail and control planes for improvement of underwater Vehicle’s maneuverability Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-07 Sheng-Ju Wu, Chun-Cheng Lin, Tsung-Lung Liu, I-Hsuan Su
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Faster pipe auto-routing using improved jump point search Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-05 Jwa-Geun Min, Won-Sun Ruy, Chul Su Park
Previous studies on pipe auto-routing algorithms generally used such algorithms as A∗, Dijkstra, Genetic Algorithm, Particle Swarm Optimization, and Ant Colony Optimization, to satisfy the relevant constraints of its own field and improve the output quality. On the other hand, this study aimed to significantly improve path-finding speed by applying the Jump Point Search (JPS) algorithm, which requires
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Research of fast point cloud registration method in construction error analysis of hull blocks Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-05 Ji Wang, Shilin Huo, Yujun Liu, Rui Li, Zhongchi Liu
The construction quality control of hull blocks is of great significance for shipbuilding. The total station device is predominantly employed in traditional applications, but suffers from long measurement time, high labor intensity and scarcity of data points. In this paper, the Terrestrial Laser Scanning (TLS) device is utilized to obtain an efficient and accurate comprehensive construction information
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Selection of PAUT probes for submarine pressure hull integrity assessment Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-08-01 Min-jae Jung, Byeong-cheol Park, Chae-og Lim, Jae-chul Lee, Sung-chul Shin
Submarine pressure hulls must withstand high hydraulic pressure and be free of defects. To improve the precision of defect detection, we herein examined different probes for optimal defect assessment by applying the Phased Array Ultrasonic Testing (PAUT) method. Two sets of probe design parameters were selected by considering pressure hull characteristics and analyzed through modeling. PAUT probes
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Numerical and experimental study on the scale effect of internal solitary wave loads on spar platforms Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-31 Xu Wang, Ji-Fu Zhou
Based on laboratory experiments and numerical simulations, the scale effect of Internal Solitary Wave (ISW) loads on spar platforms is investigated. First, the waveforms, loads, and torques on the spar model at a laboratory obtained by the experiments and simulations agree well with each other. Then, a prototype spar platform is simulated numerically to elucidate the scale effect. The scale effect
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Collision risk assessment based on the vulnerability of marine accidents using fuzzy logic Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-30 Yancai Hu, Gyei-Kark Park
Based on the trend, there have been numerous researches analysing the ship collision risk. However, in this scope, the navigational conditions and external environment are ignored or incompletely considered in training or/and real situation. It has been identified as a significant limitation in the navigational collision risk assessment. Therefore, a novel algorithm of the ship navigational collision
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Study on the effect of corrosion defects on VIV behavior of marine pipe using a new defective pipe element Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-30 He Zhang, Chengkan Xu, Xinyi Shen, Jianqun Jiang
After long-term service in deep ocean, pipelines are usually suffered from corrosions, which may greatly influence the Vortex-Induced Vibration (VIV) behavior of pipes. Thus, we investigate the VIV of defective pipelines. The geometric nonlinearity due to large deformation of pipes and nonlinearity in vortex-induced force are simulated. This nonlinear vibration system is simulated with finite element
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Experimental investigation of the whirl and generated forces of rotating cylinders in still water and in flow Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-30 Wei Chen, Chang-Kyu Rheem, Yongshui Lin, Ying Li
The whirl and generated forces of rotating cylinders with different diameters placed in still water and in flow are studied experimentally. For the rotating cylinders in still water, the Same Frequency Whirl (SFW) and Different Frequency Whirl (DFW) have been identified and illustrated. The corresponding SFW and DFW areas are divided. The Root Mean Square (RMS) values of the generated force coefficient
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Wake dynamics of a 3D curved cylinder in oblique flows Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-29 Soonhyun Lee, Kwang-Jun Paik, Narakorn Srinil
Three-dimensional numerical simulations were performed to study the effects of flow direction and flow velocity on the flow regime behind a curved pipe represented by a curved circular cylinder. The cylinder is based on a previous study and consists of a quarter segment of a ring and a horizontal part at the end of the ring. The cylinder was rotated in the computational domain to examine five incident
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Experimental study on the effects of stern bulb arrangement on the slamming load Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-29 Jongyeol Park, Ju Hyuck Choi, Hyun-ho Lee, Shin Hyung Rhee
The present study concerns the stern slamming load of container carriers, with stern bulb arrangement variation. First, a series of wedge drop tests were conducted using simple wedge models with fixed deadrise angles, and tests with the cross-section models of practical container carrier sterns were followed. The deadrise angle of the simple wedge ranged from 0° to 10°. The pressure measurement results
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Numerical simulation in time domain to study cross-flow VIV of catenary riser subject to vessel motion-induced oscillatory current Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-08 Kun Liu, Kunpeng Wang, Yihui Wang, Yulong Li
The present study proposes a time domain model for the Vortex-induced Vibration (VIV) simulation of a catenary riser under the combination of the current and oscillatory flow induced by vessel motion. In this model, the hydrodynamic force of VIV comprises excitation force, hydrodynamic damping and added mass, which are taken as functions of the non-dimensional frequency and amplitude ratio. The non-dimensional
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Influence of head structure on hydrodynamic characteristics of transonic motion projectiles Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-07-06 Rui Wang, Zhong Yao, Daqin Li, Baocheng Xu, Jiawen Wang, Xiaobin Qi
The hydrodynamic characteristic of transonic motion projectiles with different head diameters are investigated by numerical simulation. Compressibility effect in liquid-phase water are modeled using the Tait state equation. The result shows that with increasing of velocity the compression waves transfer to shock waves,which cause the significant increasing of pressure and decreasing the dimensions
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Performance study of a simplified shape optimization strategy for blended-wing-body underwater gliders Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-06-02 Chengshan Li, Peng Wang, Tianbo Li, Huachao Dong
Shape design optimization for Blended-wing-body Underwater Gliders (BWBUGs) is usually computationally expensive. In our previous work, a simplified shape optimization (SSO) strategy is proposed to alleviate the computational burden, which optimizes some of the Sectional Airfoils (SAs) instead of optimizing the 3-D shape of the BWBUG directly. Test results show that SSO can obtain a good result at
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A study on prediction of whipping effect of very large container ship considering multiple sea states Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-05-26 Beomil Kim, Joonmo Choung
In the design stage of the very large container ships, some methodologies for the whipping effects have been developed, but most of them are based on single sea state. We developed a methodology that considers multiple sea states. Fluid-structure Interaction (FSI) analyses with one dimensional structural model were carried out to capture slamming-induced transient whipping behaviors. Because of the
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Machine Learning Methodology for Management of Shipbuilding Master Data Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-05-21 Ju Hyeon Jeong, Jong Hun Woo, JungGoo Park
The continuous development of information and communication technologies has resulted in an exponential increase in data. Consequently, technologies related to data analysis are growing in importance. The shipbuilding industry has high production uncertainty and variability, which has created an urgent need for data analysis techniques, such as machine learning. In particular, the industry cannot effectively
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Estimation of ship operational efficiency from AIS data using big data technology Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-05-21 Seong-Hoon Kim, Myung-Il Roh, Min-Jae Oh, Sung-Woo Park, In-Il Kim
To prevent pollution from ships, the Energy Efficiency Design Index (EEDI) is a mandatory guideline for all new ships. The Ship Energy Efficiency Management Plan (SEEMP) has also been applied by MARPOL to all existing ships. SEEMP provides the Energy Efficiency Operational Indicator (EEOI) for monitoring the operational efficiency of a ship. By monitoring the EEOI, the shipowner or operator can establish
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Numerical investigation on the effect of baffles on liquid sloshing in 3D rectangular tanks based on nonlinear boundary element method Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-05-18 Yanmin Guan, Caihong Yang, Ping Chen, Li Zhou
The numerical simulation of liquid sloshing in the three-dimensional tanks under horizontal excitation and roll excitation was carried out, and the inhibition effect of different baffles on the sloshing phenomenon was investigated. The numerical calculations were carried out by the nonlinear Boundary Element Method (BEM) with Green's theorem based on the potential flow, which was conducted with the
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Numerical simulation of ice loads on a ship in broken ice fields using an elastic ice model Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-05-18 Chao Wang, Xiaohan Hu, Taiping Tian, Chunyu Guo, Chunhui Wang
The finite element method is used to simulate the navigation of an ice-area bulk carrier in broken ice fields. The ice material is defined as elastic, and the simulations are accomplished at four model speeds and three ice concentrations. The movements of ice floes in the simulation are consistent with those in the model test, and the percentage deviation of the numerical ice resistance from the ice
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Vector form intrinsic finite-element analysis of static and dynamic behavior of deep-sea flexible pipe Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-05-11 Han Wu, Xiaohui Zeng, Jianyu Xiao, Yang Yu, Xin Dai, Jianxing Yu
The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value
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Prediction of fully plastic J-integral for weld centerline surface crack considering strength mismatch based on 3D finite element analyses and artificial neural network Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-04-29 Chuanjie Duan, Shuhua Zhang
This work mainly focuses on determination of the fully plastic J-integral solutions for welded center cracked plates subjected to remote tension loading. Detailed three-dimensional elastic–plastic Finite Element Analyses (FEA) were implemented to compute the fully plastic J-integral along the crack front for a wide range of crack geometries, material properties and weld strength mismatch ratios for
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Ultimate strength of stiffened panels subjected to non-uniform thrust Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-04-20 Konstantinos N. Anyfantis
The current study is focused on the evaluation of the ultimate strength of stiffened panels found in ship hull structures that are subjected to combined uniaxial thrust, in-plane and out-of-plane bending moments. This loading condition, which is in general ignored when performing buckling checks, applies to representative control geometries (stiffener with attached plating) as a consequence of the
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Experimental and numerical study of autopilot using Extended Kalman Filter trained neural networks for surface vessels Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-04-08 Yuanyuan Wang, Shuhong Chai, Hung Duc Nguyen
Due to the nonlinearity and environmental uncertainties, the design of the ship's steering controller is a long-term challenge. The purpose of this study is to design an intelligent autopilot based on Extended Kalman Filter (EKF) trained Radial Basis Function Neural Network (RBFNN) control algorithm. The newly developed free running model scaled surface vessel was employed to execute the motion control
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A numerical investigation on the nominal wake of KVLCC2 model ship in regular head waves Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-02-15 Hyun-Woo Shin, Kwang-Jun Paik, Yoon-Ho Jang, Myeoung-Jin Eom, Sungwook Lee
Analysis of the propulsion performance considering ship motion in waves is an important factor for the efficient operation of a ship. The interaction between the propeller and the free surface due to the ship motion in waves has a significant influence on the propulsion performance. However, most recent studies regarding the hydrodynamic performance of ships in waves focus on the added resistance,
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Effects of nonlinear FK (Froude- Krylov) and hydrostatic restoring forces on arctic-spar motions in waves Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-02-04 HaKun Jang, MooHyun Kim
An Arctic Spar is characterized by its conical shape near the waterline. In this case, the nonlinear effects from its irregular hull shape would be significant if there is either a large amplitude floater motion or steep wave conditions. Therefore, in this paper, the nonlinear effects of an Arctic Spar are numerically investigated by introducing a weakly nonlinear time-domain model that considers the
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Influence of second order wave excitation loads on coupled response of an offshore floating wind turbine Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-02-04 Zhenju Chuang, Shewen Liu, Yu Lu
This paper presents an integrated analysis about dynamic performance of a Floating Offshore Wind Turbine (FOWT) OC4 DeepCwind with semi-submersible platform under real sea environment. The emphasis of this paper is to investigate how the wave mean drift force and slow-drift wave excitation load (Quadratic transfer function, namely QTF) influence the platform motions, mooring line tension and tower
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Snapping shrimp noise detection and mitigation for underwater acoustic orthogonal frequency division multiple communication using multilayer frequency Int. J. Nav. Archit. Ocean Eng. (IF 2.242) Pub Date : 2020-01-18 Jongmin Ahn, Hojun Lee, Yongcheol Kim, Jeahak Chung
This paper proposes Snapping Shrimp Noise (SSN) detection and corrupted Orthogonal Frequency Division Multiplexing (OFDM) reconstruction methods to increase Bit Error Rate (BER) performance when OFDM transmitted signal is corrupted by impulsive SSNs in underwater acoustic communications. The proposed detection method utilizes multilayer wavelet packet decomposition for detecting impulsive and irregularly