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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Advanced Research in Ocean Engineering
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Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 1, Issue 4 - Dec 2015
Volume 1, Issue 3 - Sep 2015
Volume 1, Issue 2 - Jun 2015
Volume 1, Issue 1 - Mar 2015
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Performance Estimation of a Tidal Turbine with Blade Deformation Using Fluid-Structure Interaction Method
Jo, Chul-Hee ; Hwang, Su-Jin ; Kim, Do-Youb ; Lee, Kang-Hee ;
Journal of Advanced Research in Ocean Engineering, volume 1, issue 2, 2015, Pages 73~84
DOI : 10.5574/JAROE.2015.1.2.073
The turbine is one of the most important components in the tidal current power device which can convert current flow to rotational energy. Generally, a tidal turbine has two or three blades that are subjected to hydrodynamic loads. The blades are continuously deformed by various incoming flow velocities. Depending on the velocities, blade size, and material, the deformation rates would be different that could affect the power production rate as well as turbine performance. Surely deformed blades would decrease the performance of the turbine. However, most studies of turbine performance have been carried out without considerations on the blade deformation. The power estimation and analysis should consider the deformed blade shape for accurate output power. This paper describes a fluid-structure interaction (FSI) analysis conducted using computational fluid dynamics (CFD) and the finite element method (FEM) to estimate practical turbine performance. The loss of turbine efficiency was calculated for a deformed blade that decreased by 2.2% with maximum deformation of 216mm at the blade tip. As a result of the study, principal causes of power loss induced by blade deformation were analysed and summarised in this paper.
Integrated Simulations of a Floating Crane Installation Vessel with DP systems in Waves
Nam, B.W. ; Hong, S.Y. ; Kim, Y.S. ; Kim, J.W. ;
Journal of Advanced Research in Ocean Engineering, volume 1, issue 2, 2015, Pages 85~93
DOI : 10.5574/JAROE.2015.1.2.085
The nonlinear time-domain analysis method was implemented to carry out a series of integrated simulations for a deep-water crane vessel system composed of four sub components, including a floating vessel, lifted equipment, hoisting cable and dynamic positioning (hereinafter DP) system. The analysis of the coupled dynamics consists of the crane vessel and equipment connected using the crane wire, and the DP is modeled according to the wind, wave and current conditions. The DP systems were numerically implemented using a classical PD feedback controller, and various simulations of the deepwater installation were conducted using different conditions in order to evaluate the global performance of the floating crane vessel combined with the DP system.
Optimal Thrust Allocation for Dynamic Positioning of Deep-sea Working Vessel
Zhao, Luman ; Roh, Myung-Il ; Hong, Jeong-Woo ;
Journal of Advanced Research in Ocean Engineering, volume 1, issue 2, 2015, Pages 94~105
DOI : 10.5574/JAROE.2015.1.2.094
In this study, a thruster allocation method of a deep-sea working vessel was proposed with the aims of producing the demanded generalized forces and moment for dynamic positioning while at the same time minimizing total power. For this, an optimization problem for thrust allocation was mathematically formulated with design variables, objective function, and constraints. The genetic algorithms (GA) was used to solve the formulated problem. The proposed method was applied to an example of finding optimal thrust allocation of the deep-sea working vessel having 5 thrusters. The result showed that the method could be used to determine better strategy for thruster allocation of the vessel as compared to existing study.
Cumulative Angular Distortion Curve of Multi-Pass Welding at Thick Plate of Offshore Structures
Ha, Yunsok ; Choi, Jiwon ;
Journal of Advanced Research in Ocean Engineering, volume 1, issue 2, 2015, Pages 106~114
DOI : 10.5574/JAROE.2015.1.2.106
In the fabrication of offshore oil and gas facilities, the significance of dimension control is growing continuously. But, it is difficult to determine the deformation of the structure during fabrication by simple lab tests due to the large size and the complicated shape. Strain-boundary method (a kind of shrinkage method) based on the shell element was proposed to predict the welding distortion of a structure effectively. Modeling of weld geometry in shell element is still a difficult task. In this paper, a concept of imaginary temperature pair is introduced to handle the effect of geometric factors such as groove shape, plate thickness and pass number, etc. Single pass imaginary temperature pair formula is derived from the relation between the groove area and the FE mesh size. By considering the contribution of each weld layer to the whole weldment, multi-pass imaginary temperature is also derived. Since the temperature difference represents the distortion increment, cumulative distortion curve can be drawn by integrating the temperature difference. This curve will be a useful solution when engineers meet some problems occurred in the shipyard. A typical example is shown about utilization of this curve. Several verifications are conducted to examine the validity of the proposed methodology. The applicability of the model is also demonstrated by applying it to the fabrication process of the heavy ship block. It is expected that the imaginary temperature model can effectively solve the modeling problem in shell element. It is also expected that the cumulative distortion curve derived from the imaginary temperature can offer useful qualitative information about angular distortion without FE analysis.
Parametric Study of Numerical Prediction of Slamming and Whipping and an Experimental Validation for a 10,000-TEU Containership
Kim, Jung-Hyun ; Kim, Yonghwan ;
Journal of Advanced Research in Ocean Engineering, volume 1, issue 2, 2015, Pages 115~133
DOI : 10.5574/JAROE.2015.1.2.115
This paper describes an approach for the numerical analysis of container ship slamming and whipping and various parameters that influence slamming and whipping. For validation purposes, the numerical analysis results were compared with experimental results obtained as part of the Wave-Induced Loads on Ships Joint Industry Project. Water entry problems for two-dimensional (2D) sections were first solved using a 2D generalized Wagner model (GWM) for various drop conditions and geometries. As the next step, the hydroelastic numerical analysis of a 10,000-TEU container ship subjected to slamming and whipping loads in waves was performed. The analysis method used is based on a fully coupled model consisting of a three-dimensional (3D) Rankine panel model, a 3D finite element model (FEM), and a 2D GWM, which are strongly coupled in the time domain. Parametric studies were carried out in both numerical and experimental tests with various forward speeds, wave heights, and wave periods. The trends observed and the validity of the numerical analysis results are discussed.
A Study on the Steering Performance and Turning Radius of Four-Rows Tracked Vehicle on Hard Ground
Oh, Jaewon ; Lee, Changho ; Min, Cheonhong ; Hong, Sup ; Cho, Huije ; Kim, Hyungwoo ;
Journal of Advanced Research in Ocean Engineering, volume 1, issue 2, 2015, Pages 134~147
DOI : 10.5574/JAROE.2015.1.2.134
This study proposes a method to determine the effective angular velocity of each motor of a specific four-rows tracked vehicle (FRTV) in order to follow a given turning radius. The configuration of the four-rows tracked vehicle is introduced, and its dynamics analysis model is built using the DAFUL commercial software. The soil has been assumed to be hard ground, and the friction force between the ground and the tracked links is calculated using the Coulomb friction model. This paper uses a simulation to show that the error in the position increased with respect to the angle of the curvatures, so a method is proposed to compensate for the error in the motion of the motors. Various simulations are then carried out to verify the proposed formulation. The effects of the soil characteristics and the driving velocity will be further investigated in future studies.