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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
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Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 30, Issue 3 - Jun 2016
Volume 30, Issue 2 - Apr 2016
Volume 30, Issue 1 - Feb 2016
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Study of Hull Form Development of Wave-Piercing-Type High-Speed Planing Boat
Jeong, Uh-Cheul ; Lee, Dong-Kun ; Jung, Ki-Seok ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 69~74
DOI : 10.5574/KSOE.2016.30.2.069
A new wave-piercing-type high-speed planing boat without a chine was developed, and its basic performance was investigated in a model test, including the resistance, trim, and sinkage. The maximum speed of the developed ship was 35 knots. The hull form was developed by combining a VSV (very slender vessel) and TH (transonic hull), which have large deadrise angles at the bow. The main dimensions were estimated by a statistical approach using actual ship data. The effect of a side fin attached at the stern near the water line was investigated from a resistance point of view. It was found that the developed hull form showed the possibility of a new concept for a high-speed planing hull without a chine, and the side fin played an important role in increasing the resistance performance by controlling the trim and sinkage in the high-speed range.
Experimental Study of Heave Responses of Subsea Equipment during Installation Operation Using Offshore Crane
Choi, Young-Myung ; Nam, Bo Woo ; Kim, Nam Woo ; Park, In Bo ; Hong, Sa Young ; Kim, Jong Wook ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 75~83
DOI : 10.5574/KSOE.2016.30.2.075
An experimental study on a subsea installation using an offshore crane was conducted. Concrete blocks, suction piles, and manifolds were considered in this study. Free decay tests were conducted to investigate the fluid characteristics of the subsea structures. The added masses of the structures were estimated. The motion response amplitudes of the subsea structures were compared for different structures and water depths. In addition, the dynamic tension transfer function of the crane wire was investigated. The root mean square values of the heave motion and the dynamic amplification factor of the wire tension were investigated in irregular waves.
One-way Coupled Response Analysis between Floating Wind-Wave Hybrid Platform and Wave Energy Converters
Lee, Hyebin ; Bae, Yoon Hyeok ; Cho, Il-Hyoung ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 84~90
DOI : 10.5574/KSOE.2016.30.2.084
In this study, a six degree-of-freedom motion analysis of a wind-wave hybrid platform equipped with numerous wave energy converters (WECs) was carried out. To examine the effect of the WECs on the platform, an analysis of one-way coupling was carried out, which only considered the power take-off (PTO) damping of the static WECs on the platform. The equation of motion of a floating platform with mooring lines in the time domain was established, and the responses of the one-way coupled platform were then compared with the case of a platform without any coupling effects from the WECs. The hydrodynamic coefficients and wave exciting forces were obtained from the 3D diffraction/radiation pre-processor code WAMIT based on the boundary element method. Then, an analysis of the dynamic responses of the floating platform with or without the WEC effect in the time domain was carried out. All of the dynamics of a floating platform with multiple wind turbines were obtained by coupling FAST and CHARM3D in the time domain, which was further extended to include additional coupled dynamics for multiple turbines. The analysis showed that the PTO damping effect on platform motions was negligible, but coupled effects between multiple WECs and the platform may differentiate the heave, roll, and pitch platform motions from the one without any effects induced by WECs.
Experimental Study on Elastic Response of Circular Cross-section Slender Body to Forced Oscillation, Waves, and Current
Park, Ji-won ; Lee, Seung-Jae ; Jo, Hyo-Jae ; Hwang, Jae-Hyuk ; Han, Sung-Hoon ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 91~99
DOI : 10.5574/KSOE.2016.30.2.091
The global demand for oil and natural gas has increased, and resource development is moving to the deep sea. Floating and flexible offshore structures such as semi-submersible, spar, and FPSO structures have been widely used. The major equipment of floating structures is always exposed to waves, currents, and other marine environmental factors, which cause structural damage. Moreover, flexible risers are susceptible to an exciting force due to the motion of the floating body. The inline and transverse responses from the three-dimensional behavior of a floating structure occur because of various forces. Typical risers are made of steel pipe and applied in the oil and gas development field, but flexible materials such as polyethylene are suitable for OTEC risers. Consequently, the optimal design of a flexible offshore plant requires a dynamic behavior analysis of slender bodies made of the different materials commonly used for offshore flexible risers. In this study, a three-dimensional motion measurement device was used to analyze the displacements of riser models induced by external force factors, and forced oscillation of a riser was linked to forced oscillation under a steady flow and regular wave condition.
Strength Assessment of High-Pressure Ball Valve for Topside Process Unit
Oh, Jeong-Sik ; Kim, Yooil ; Jeong, Nakshin ; Kim, Sangmyung ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 100~108
DOI : 10.5574/KSOE.2016.30.2.100
A high-pressure ball valve was developed, and both the structural strength and sealing performance were assessed based on a nonlinear finite element analysis. Different parts were modeled with solid elements and assembled, taking into account both contact and sliding effects. Three different loading scenarios were analyzed, including a high-pressure closure test and fire and shell test conditions. The structural safety of each part was checked under each loading condition, and the sealing performance was also investigated to validate the performance of the valve.
Damage Evaluation of Flexible Concrete Mattress Considering Steel Reinforcement Modeling and Collision Angle of Anchor
Ryu, Yeon-Sun ; Cho, Hyun-Man ; Kim, Seo-Hyun ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 109~116
DOI : 10.5574/KSOE.2016.30.2.109
A flexible concrete mattress (FCM) is a structural system for protecting submarine power or communication cables under various load types. To evaluate its of protection performance, a numerical analysis of an FCM under an anchor collision was performed. The explicit dynamics of the finite element analysis program ANSYS were used for the collision analysis. The influences of the steel reinforcement modeling and collision angle of the anchor on the collision behavior of the FCM were estimated. The FCM damage was evaluated based on the results of the numerical analysis considering the numerical modeling and collision environment.
Measurement of Real Deformation Behavior in C-type Lng Mock-up Tank using Strain Gage
Jung, Won-Do ; Kim, Tae-Wook ; Kim, Jeong-Hyeon ; Lee, Do-Young ; Chun, Min-Sung ; Lee, Jae-Myung ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 117~124
DOI : 10.5574/KSOE.2016.30.2.117
A C-type LNG mock-up tank was constructed to evaluate the durability of the tank and its structural safety. An experimental strain analysis system equipped with strain gages was designed to investigate the structural behavior of the inner tank at a high hydraulic pressure. In addition, the insulation used in the space between the inner tank and outer tank had a compressive strength and the inner tank thickness of the cylindrical shell and hemisphere was 4.0 mm, which was designed to be thinner than the existing rules. The strains on the inner tank were measured with increasing pressure, and these measurements were compared and analyzed at the strain gage attachment points.
Study on Vertical Axis Water Turbine with Movable Dual Blades
Kim, Do-Hyung ; Ahn, Byoung-Kwon ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 125~133
DOI : 10.5574/KSOE.2016.30.2.125
In this paper, we propose a vertical axis water turbine with dual blades. A parametric study was conducted using numerical analyses. First, a two-dimensional finite-volume analysis with a commercial code was used to find the pitch angle of the main blade under different tip speed ratio conditions. Second, we developed a potential-based panel method to find the best configuration of the inner blades. Experimental tests were conducted at the circulating water channel of Chungnam National University. Various configurations of the dual blades were considered, and their performances were comparatively investigated. The results showed that the turbine with movable dual blades produces a constant torque and tip speed ratio at various flow rates.
Design of Pitch Limit Detection Algorithm for Submarine
Park, Jong-Yong ; Kim, Nakwan ; Shin, Yong-Ku ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 134~140
DOI : 10.5574/KSOE.2016.30.2.134
An envelope protection system is a control system that allows a submarine to operate freely using its own operational envelope without exceeding the structural limit, dynamic limit, and control input limit. In this paper, an envelope protection system for the pitch angle of a submarine is designed using a dynamic trim algorithm. A linear quadratic regulator and artificial neural network are used for the true dynamics approximation. A submarine maneuvering simulation program developed using experimental data is used to validate the designed envelope protection system. Simulation results show the effectiveness of the designed envelope protection system.
Consideration of Launch and Recovery Systems for Operation of Underwater Robot from Manned Platform
Lee, Ki-Young ;
Journal of Ocean Engineering and Technology, volume 30, issue 2, 2016, Pages 141~149
DOI : 10.5574/KSOE.2016.30.2.141
In this technical note, the issues and challenges for the launch and recovery systems (LARS) and related techniques for the operation of an underwater robot from a manned platform are considered. Various types of LARS fitted to specific manned platforms, surface or sub-surface, are surveyed and categorized. The current UUV launch and recovery systems from surface ships and submarines utilize time consuming processes. As underwater robot technologies evolve and their roles are defined, safe and effective launch and recovery methods should be developed capable of reliable and efficient operations, particularly at a high sea state. To improve the existing underwater robot capabilities, LARS technology maturation is required in the near term, leading to the ability to incorporate autonomous LARS for an underwater robot on a manned platform. In the near term, particular emphasis should be placed on UUV LARS, which are surface ship based, with submarine based systems in the long term. Furthermore, for a dedicated LARS ship, independent of the existing host ship type, particular emphasis should be given to fully utilizing the capabilities of underwater robots.