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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
Editor in Chief :
Volume & Issues
Volume 27, Issue 6 - Dec 2013
Volume 27, Issue 5 - Oct 2013
Volume 27, Issue 4 - Aug 2013
Volume 27, Issue 3 - Jun 2013
Volume 27, Issue 2 - Apr 2013
Volume 27, Issue 1 - Feb 2013
Selecting the target year
Study of Hull Form Development and Resistance Performance of Catamaran-type High Speed Fishing Leisure Boat
Jeong, Uh-Cheul ; Kwon, Soo-Yeon ; Choi, Ji-Hoon ; Kim, Do-Jung ; Hong, Ki-Sup ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 1~6
DOI : 10.5574/KSOE.2013.27.6.001
A 25ft class fishing leisure boat is developed, and the resistance performances are investigated by a model test in a high-speed circulating water channel. The design speed of the developed ship is 25 knots using a 150 ps outboard engine. A catamanan type hull form using a planing section is adopted considering the Froude number and large deck area. The effect of a center body attached on the bottom of the cross deck is studied under various conditions. Wave patterns are observed to make clear the relationship between the resistance performance and the wave characteristics. The results show that the shape of the center body and the position of the chine line can have a strong effect on the resistance performance in a certain velocity range.
Numerical Simulation on Dynamic Characteristics of Offshore Seaweed Culture Facility
Lee, Seonmin ; Hwang, Hajung ; Na, Won-Bae ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 7~15
DOI : 10.5574/KSOE.2013.27.6.007
Eco-friendly and sustainable seaweed biomass energy have been under the spotlight as the future of renewable energy. However, seaweed culture is primarily conducted inshore, with the research on offshore culture still in an early stage. For massive biomass production, a systematic engineering approach is required to devise offshore seaweed culture facilities rather than the conventional empirical ones. To establish the fundamental behavior of seaweed culture facilities, the dynamic characteristics of a seaweed culture facility were analyzed in the study. For this purpose, numerical analyses of the seaweed culture facility (a frame type) were carried out by using the hydrodynamic simulation program ANSYS-AQWA. For the analysis, environmental loads were considered using the wave spectra and co-linear current; mooring variables were selected as parameters; and time domain analyses were carried out to acquire the time series responses and eventually the dynamic characteristics. Finally, the mooring performance was evaluated. It was found that the motion could be controlled by adjusting the buoyancy and mooring slope.
Preliminary Design of mooring line in floating wave energy farm
Jung, DongHo ; Song, JaeHa ; Shin, SeungHo ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 16~21
DOI : 10.5574/KSOE.2013.27.6.016
In this paper, the mooring system for a floating wave energy farm is designed based on a two-dimensional analysis. The mooring system uses an anchorless mooring line linking two floaters in a floating wave energy farm. The basic equation to determine the length of the mooring line between the two floaters is proposed. The other properties such as the diameter and pretension are taken from the mooring line for a single floater. The dynamic behavior and safety of the designed mooring system under extreme ocean conditions are analyzed with the commercial software Orcaflex. A numerical study shows the stability and high safety in tension of the designed mooring lines for a floating wave energy farm. The proposed anchorless mooring system for a floating wave energy farm results in a considerable reduction in the length of the mooring line, contributing to the economics of a floating wave energy farm.
Improved design for mooring line with lumped weight at seabed
Song, JaeHa ; Shin, SeungHo ; Jung, DongHo ; Kim, HyeonJu ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 22~26
DOI : 10.5574/KSOE.2013.27.6.022
The purpose of this study was to improve the design of a mooring line by attaching a lumped mass to it on the seabed. A numerical analysis of the redesigned mooring system is performed to analyze the effect of the weight of the attached lumped mass using the commercial software Orcaflex. The ultimate tension of the mooring system with the lumped mass is compared with that of a bare mooring line in the original design. An appropriately designed weight for the lumped mass is found to induce a critical lifted point in the mooring line by floater motion in the ultimate condition to move toward the floater position from the anchor point, while maintaining a similar safety factor for the mooring line. On the other hand, it is shown that excess weight for the lumped mass induces snapping in a mooring line, resulting in low safety factor for the mooring system. The distance between lumped weights is shown to be a minor parameter affecting the safety of a mooring line, although a shorter line has an advantage from an economic point of view. Using the optimal weight for the lumped mass attached to the mooring line on a seabed reduces the mooring line length and installation area occupied by a mooring system under real sea conditions.
Experimental study on motions of VLCO for wave power generation (2. Multiple floating bodies)
Lee, Seung-Chul ; Goo, Ja-Sam ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 27~31
DOI : 10.5574/KSOE.2013.27.6.027
The structure of a variable liquid column oscillator(VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system for absorbing the high kinetic energy of the accelerated motions of multiple floating bodies using an air-spring effect produced the installation of inner air chambers. Thus, a VLCO can improve the energy efficiency of the activating object type of wave energy converters made by the Pelamis Company. In this research, an experiment was performed in two cases: with the top valves closed and open. The floating bodies were connected by hinges. The effect of the internal flow was estimated by comparing the results for the closed and open valves.
Numerical Investigation on the Applicability of Wave-Induced Swirl Water Chamber for Wave Power Generation in Coastal Water of Korea
Choi, Jung-Kyu ; Kim, Hyoung-Tae ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 32~42
DOI : 10.5574/KSOE.2013.27.6.032
In this paper, a wave-induced swirl water chamber (SWC) for breakwater and wave power generation is introduced and its applicability to wave power generation in the coastal waters of Korea is investigated. The SWC type of wave power generation is a way to drive a turbine using the unidirectional swirl flow that is induced in the back of a curtain wall of a breakwater due to incident waves. The typical wave characteristics are obtained by analyzing the annual statistical wave data from KHOA (Korea Hydrographic and Oceanographic Administration). A numerical analysis is carried out on the variations in the SWC entrance height, wave height, and different installation conditions. For the numerical analysis, a commercial code, Fluent based on FVM, is used. As the entrance height decreases, the mass flow rate through the entrance is rarely changed, whereas the magnitude of the flow velocity of the smaller entrance height is greater than the other ones, which is better for the formation of an SWC swirl flow inside and the flow kinetic energy at the entrance. In cases of installation conditions where a wall is place behind and under SWC, it has been shown that the mass flow rate through the entrance is greater than that in the open condition, and sufficient flow kinetic energy is generated in the entrance for wave power generation. However, the swirl flow kinetic energy is relatively small. Thus, in the future, it is necessary to study the swirl flow generation, which is affected by the SWC shape.
Stability Evaluation of Floating Dock during Construction and Launching of Caisson for Breakwater
Seok, Jun ; Park, Jong-Chun ; Jeong, Se-Min ; Kim, Sung-Yong ; Kang, Heon-Yong ; Kim, Moo-Hyun ; Kang, Yoon-Koo ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 43~55
DOI : 10.5574/KSOE.2013.27.6.043
In general, huge caissons for breakwaters have been constructed on land or a floating dock. In the case of the construction on a floating dock, a 4 step installation procedure is involved: i) construction on a floating dock, ii) transportation by the floating dock to an area near the target sea, iii) launching from the floating dock, and iv) transference by tug-boats to the installation site. It is especially important to pay attention to the dynamic stability of the floating dock against the conditions in the sea during steps i) and iii). In this paper, the static and dynamic stabilities of a caisson on a floating dock are evaluated based on IMO rules during the construction and launching of the caisson on a floating dock by using independent commercial S/Ws such as NAPA, WAMIT, and CHARM3D.
Modeling and controller design of crabbing motion for auto-berthing
Park, Jong-Yong ; Kim, Nakwan ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 56~64
DOI : 10.5574/KSOE.2013.27.6.056
Crabbing motion is the pure sway motion of a ship without surge velocity. Thus, it can be applied to a berthing operation. Crabbing motion is induced by a peculiar operation method called the push-pull mode. The push-pull mode is induced by using a combination of the main propeller and side thruster. Two propellers generating the same amounts of thrust and rotating in opposite directions produce some yawing moment on a vessel but do not induce longitudinal motion. With the additional operation of side thrusters, the push-pull mode is used to induce a large amount of lateral force. In this paper, three-degree-of-freedom equations of motion such as for the surge, sway, and yaw are constructed for the crabbing motion. Based on these equations of motion, a feedback linearization control method is applied to auto-berthing control for a twin-screw ship with side thrusters. The controller can deal with the nonlinearity of a system, which is present in the berthing maneuver of a twin screw ship. A simulation of the auto-berthing of a ship is performed to validate the performance of the designed controller.
Finite Element Analysis of Carbon Fiber Reinforced Plastic Frame for Multi-legged Subsea Robot
Yoo, Seong-Yeol ; Jun, Bong-Huan ; Shim, Hyungwon ; Lee, Pan-Mook ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 65~72
DOI : 10.5574/KSOE.2013.27.6.065
This paper describes a finite element analysis (FEA) of the body frame of a subsea robot, Crabster200 (CR200). CR200 has six legs for mobility instead of screw type propellers, which distinguishes it from previous underwater robots such as remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs). Another distinguishing characteristic is the body frame, which is made of carbon fiber reinforced plastic (CFRP). This body frame is designed as a rib cage structure in order to disperse the applied external loads and reduce the weight. The frame should be strong enough to support many devices for exploration and operation underwater. For a reasonable FEA, we carried out specimen tests. Using the obtained material properties, we performed a modal analysis and FEA for CR200 with a ready posture. Finally, this paper presents the FEA results for the CFRP body frame and the compares the characteristics of CFRP with conventional material, aluminum.
Study of Dynamic Characteristics of West Coast Saemangeum Sand by Torsional Shear Test
Jeon, Hong-Woo ; Son, Su-Won ; Kim, Jin Man ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 73~80
DOI : 10.5574/KSOE.2013.27.6.073
The dynamic characteristics of west coast sand were investigated in order to evaluate the design properties of the offshore wind turbine foundations to be constructed in the West Sea. Torsional shear tests were performed at different confining pressures and densities on specimens constituted by the dry fluviation method. The strain-dependent shear modulus and damping curves were obtained, together with modulus degradation curves. The results show that the confining pressure is more influential on the dynamic characteristics of the sand than the density. It was also found that the dynamic curves from this study were similar to those proposed by others. The modulus degradation ratio
varies slightly at a small strain level, but increases significantly once beyond the intermediate strain level.
Study on Steering Ratio of Four-Row Rigid Tracked Vehicle on Extremely Cohesive Soft Soil Using Numerical Simulation
Kim, Hyung-Woo ; Lee, Chang-Ho ; Hong, Sup ; Choi, Jong-Su ; Yeu, Tae-Kyeong ; Min, Cheon-Hong ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 81~89
DOI : 10.5574/KSOE.2013.27.6.081
This paper considers the steering characteristics of a four-row tracked vehicle crawling on extremely cohesive soft soil, where each side is composed of two parallel tracks. The four-row tracked vehicle (FRTV) is assumed to be a rigid body with 6-DOF. A dynamic analysis program for the tracked vehicle is developed using the Newmark-
method based on an incremental-iterative scheme. A terra-mechanics model of an extremely cohesive soft soil is implemented in the form of the relationships of the normal pressure to the sinkage, the shear resistance to the shear displacement, and the dynamic sinkage to the shear displacement. In order to investigate the steering characteristics of the four-row tracked vehicle, a series of dynamic simulations is conducted with respect to the distance between the left and right tracks (pitch), steering ratios, driving velocity, reference track velocity, lengths of the tracks, and properties of the cohesive soft soil. Through these numerical simulations, the possibility of using a kinematic steering ratio is explored.
Reflection and Transmission Coefficients for Rubble Mound Breakwaters in Busan Yacht Harbor
Park, O Young ; Dodaran, Asgar Ahadpour ; Bagheri, Pouyan ; Kang, Kyung Uk ; Park, Sang Kil ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 90~94
DOI : 10.5574/KSOE.2013.27.6.090
This paper reports the results obtained for there flection and transmission coefficients on rubble mound breakwaters in Busan Yacht Harbor. A2D physical model test was conducted in the wave flume at the Coastal Engineering Research Laboratory at Pusan National University, Busan, South Korea. In this study, physical model tests were completed to further our understanding of the hydrodynamic processes that surround a rubble mound structure subjected to irregular waves. In particular, the reflection and transmission coefficients, as well as the spectrum transformation, were analyzed. This analysis suggests that with an increase in wave height around a rubble mound, the reflection coefficient drastically increases at each water level (HHW or MSL or LLW). Moreover, when the water level changes from HHW to LLW, the reflection coefficient is suddenly reduced. A further result of the analysis is that the transmission coefficient strongly drops away from the rear of the structure. Finally, in regard to the rubble mound breakwater in Busan Yacht Harbor, a consideration of the reflection and transmission coefficients plays an important role in the design.
Fabrication of piezoelectric PZT thick film by aerosol deposition method
Kim, Ki-Hoon ; Bang, Kook-Soo ; Park, Chan ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 95~99
DOI : 10.5574/KSOE.2013.27.6.095
Lead zirconate titanate (PZT) thick films with a thickness of
were fabricated on silicone substrates using an aerosol deposition method. The starting powder, which had diameters of
, was observed using SEM. The average diameter (
. An XRD analysis showed a typical perovskite structure, a mixture of the tetragonal phase and rhombohedral phase. The as-deposited film with nano-sized grains had a fairly dense microstructure without any cracks. The deposited film showed a mixture of an amorphous phase and a very fine crystalline phase by diffraction pattern analysis using TEM. The as-deposited films on silicon were annealed at a temperature of
. A 20-
thick PZT film was torn out as a result of the high compressive stress between the PZT film and substrate.
Study on Sea Surface Reconstruction Using Sequent Radar Images
Park, Jun-Soo ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 100~105
DOI : 10.5574/KSOE.2013.27.6.100
This paper presents a sea surface reconstruction method that uses measured radar images by applying filtering techniques and identifying wave characteristics of the surrounding the Ieodo ocean research station using WaveFinder (X-band wave measurement radar), which is installed in the station. In addition, the results obtained from real radar images are used to verify the reconstructed sea surface. WaveFinder is a marine system that was developed to measure wave information in real time. The WaveFinder installed in the station could acquire sequent images for the sea surface at constant time intervals to obtain real time information (Wave height, mean wave period, wave directionality, etc.) for the wave by getting a three-dimensional spectrum by applying an FFT algorithm to the acquired sequent images and wave dispersion relation. In particular, we found the wave height using the SNR (Signal to noise ratio) of the acquired images. The wave information measured by WaveFinder could be verified by comparing and analyzing the results measured using the wave measurement instrument (Sea level monitor) in the station. Additionally, the wave field around the station could be reconstructed through the three-dimensional spectrum and the inverse FFT filtering from the analyzed results for the measured radar images. We verified the applicability of the sea surface reconstruction method by comparing the measured and simulated sea surfaces.
Development of High Pressure Pump of 50MPa class for Ship Painting
Kim, Soon-Kyung ; Kim, Dong-Keon ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 106~111
DOI : 10.5574/KSOE.2013.27.6.106
In this study, numerical simulations and performance evaluation has been carried out to investigate performance characteristics of air-type high pressure piston pump. ANSYS and CFX were applied for analyzing the structure and flow behavior of air-type high pressure piston pump, respectively. The performance evaluation of high pressure piston pump was performed experimentally, the results were compared with simulation. It was found that the freezing phenomenon was improved by 20% and the pressure fluctuation decreased by 50%, compared with the previous pump.
Result Analysis of Sea Trial Test for Offshore Fishing Boat Attached FRP Rudder
Park, Chung-Hwan ; Jang, Ho-Yun ; Park, Myung-Sik ; Im, Nam-Kyun ;
Journal of Ocean Engineering and Technology, volume 27, issue 6, 2013, Pages 112~118
DOI : 10.5574/KSOE.2013.27.6.112
This paper reports the results of a comparative study on rudder performance between the steel rudders that have been used in coastal angling fishing boats in the 20-GT class and the newly developed FRP composite material rudders. In order to compare the rudder performances of these two types, a sea trial test was carried out to investigate the speed performance, fuel consumption, and ship`s turning ability. The results showed that the sea trial performance of the FRP composite rudder was better than that of the steel rudder type in terms of the sea speed, fuel consumption rate, and turning ability.