Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
Editor in Chief :
Volume & Issues
Volume 30, Issue 3 - Jun 2016
Volume 30, Issue 2 - Apr 2016
Volume 30, Issue 1 - Feb 2016
Selecting the target year
Experimental Study on Performance of Wave Energy Converter System with Counterweight
Han, Sung-Hoon ; Jo, Hyo-Jae ; Lee, Seung-Jae ; Hwang, Jae-Hyuck ; Park, Ji-Won ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 1~9
DOI : 10.5574/KSOE.2016.30.1.001
In order to convert wave energy into large quantities of high-efficiency power, it is necessary to study the optimal converter system appropriate for the environment of a specific open ocean area. A wave energy converter system with a counterweight converts the translation energy induced from the heave motion of a buoy into rotary energy. This experimental study evaluated the primary energy conversion efficiency of the system, which was installed on an ocean generating basin with a power take-off system. Moreover, this study analyzed the energy conversion performance according to the weight condition of the buoy, counter-weight, and flywheel by changing the load torque and wave period. Therefore, these results could be useful as basic data such as for the optimal design of a wave energy converter with a counterweight and improved energy conversion efficiency.
A Study on the Simulation-based Design for Optimum Arrangement of Buoyancy Modules in Marine Riser System
Oh, Jae-Won ; Park, Sanghyun ; Min, Cheon-Hong ; Cho, Su-Gil ; Hong, Sup ; Bae, Dae-Sung ; Kim, Hyung-Woo ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 10~17
DOI : 10.5574/KSOE.2016.30.1.010
This paper reports a simulation-based design method for the optimized arrangement design of buoyancy modules in a marine riser system. A buoyancy module is used for the safe operation and structural stability of the riser. Engineers design buoyancy modules based on experience and experimental data. However, they are difficult to design because of the difficulty of conducting real sea experiments and quantifying the data. Therefore, a simulation-based design method is needed to tackle this problem. In this study, we developed a simulation-based design algorithm using a multi-body dynamic simulation and genetic algorithm to perform optimization arrangement design of a buoyancy module. The design results are discussed in this paper.
Performance Analysis of Stabilizer Fin Applied Coanda System
Seo, Dae-Won ; Lee, Se-Jin ; Oh, Jungkeun ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 18~24
DOI : 10.5574/KSOE.2016.30.1.18
Stabilizer fins are installed on each side of a ship to control its roll motion. The most common stabilizer fin is a rolling control system that uses the lift force on the fin surface. If the angle of attack of a stabilizer fin is zero or the speed is zero, it cannot control the roll motion. The Coanda effect is well known to generate lift force in marine field. The performance of stabilizer fin that applies the Coanda effect has been verified by model tests and numerical simulations. It was found that a stabilizer fin that applied the Coanda effect at Cj = 0.085 and a zero angle of attack exactly coincided with that of the original fin at α = 26°. In addition, the power needed to generate the Coanda effect was not high compared to the motor power of the original stabilizer fin.
Prediction of Hydrodynamic Coefficients for Underwater Vehicle Using Rotating Arm Test
Jeong, Jae-Hun ; Han, Ji-Hun ; Ok, Jihun ; Kim, Hyeong-Dong ; Kim, Dong-Hun ; Shin, Yong-Ku ; Lee, Seung-Keon ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 25~31
DOI : 10.5574/KSOE.2016.30.1.025
In this study, hydrodynamic coefficients were obtained from a Rotating Arm (RA) test, which is one of the captive model tests used to provide accurate coefficients in the control motion equation of an underwater vehicle. The RA test was carried out at the RA facility of ADD (Agency for Defense Development), and the forces and moments acting on the underwater vehicle were measured using a six-axis waterproof gage. A multiple regression analysis was used in the analysis of the measured data. The experimental results were also verified by comparison with the theoretical values of the previous linear coefficients. In addition, the stability indices in the horizontal plane were calculated using the linear and nonlinear coefficients, and the dynamic stability of the underwater vehicle was estimated to have a good dynamic performance with a depth ratio of 6.0.
Backward Path Following Using Pure Pursuit Guidance and Nonlinear Guidance for UUV under Strong Current
Lee, Jooho ; Kim, Nakwan ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 32~43
DOI : 10.5574/KSOE.2016.30.1.032
A UUV needs to have a robust path following performance because of unpredicted current disturbances. Because the desired path of a UUV is usually designed by considering the locations of obstacles or geographical features of the operation region, the UUV should stay on the desired path to avoid damage or loss of the vehicle. However, conventional path following methods cannot deal with strong countercurrent disturbances. Thus, the UUV may deviate from the desired path. In order to avoid such deviation, a backward path following method is suggested. This paper proposes a path following method that combines pure pursuit guidance and nonlinear guidance for the UUV under an unpredicted strong ocean current. For a stable path following system, this paper suggests that the UUV adjust its heading to the current direction using the pure pursuit guidance method when the system is in an unstable region, or the UUV follows the desired path with nonlinear guidance. By combining the pure pursuit guidance and nonlinear guidance, it was possible to overcome the drawbacks of each path following method in the reverse path following case. The efficiency of the proposed method is shown through simulation results compared to those of the pure pursuit method and nonlinear guidance method.
Experimental Study on Behavior of Green Water for Rectangular Structure
Chae, Young Jun ; Lee, Kang Nam ; Jung, Kwang Hyo ; Suh, Sung Bu ; Lee, Jae Yong ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 44~50
DOI : 10.5574/KSOE.2016.30.1.044
An experimental study was performed to investigate the behavior of green water on a structure with a rectangular cross section under wave conditions, along with the flow characteristics in bubbly water flow. An experiment was conducted in a two-dimensional wave flume using an acrylic model (1/125) of FPSO BW Pioneer operating in the Gulf of Mexico under its design wave condition. The occurrence of green water, including its development, in front of the model was captured using a high-speed Charge Coupled Device (CCD) camera with the shadowgraph technique. Using consecutive images, the generation procedure for green water on the model was divided into five phases: flip through, air entrapment, wave run-up, wave overturning, and water shipping. In addition, the distinct water elevations of the green water were defined as the height of flip through, height of splashing jet, and height of freeboard exceedance, and showed a linear relationship with the incoming wave height.
Optimization of Friction Welding Conditions for Production of Hose Nipple for Marine Transport
Kim, Dong-Gyu ; Kim, Yeuk-Ran ; Kong, Yu-Sik ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 51~56
DOI : 10.5574/KSOE.2016.30.1.051
In this study, for the tube-to-tube friction welding of hose nipple materials, the main parameters of friction welding were investigated using tensile tests, Vickers hardness surveys of the bond area (HAZ), and observations of the microstructure to increase the quality of friction welding based on visual examination. As-welded and post weld heat treated (PWHT) specimens were tested. The optimal welding conditions were found to be n = 1000 rpm, HP = 10 MPa, UP = 15 MPa, HT = 9 s, and UT = 5 s when the metal loss (Mo) was 7.5 mm. Furthermore, the peak of the hardness distribution of the friction welded joints could be eliminated by PWHT. Moreover, the two materials of the friction weld were thoroughly mixed with a well-combined structure of micro-particles, without any molten material, particle growth, or defects.
Performance Evaluation and Technical Development of Eco-environmental Photovoltaic Leisure Ship with Sail-controlling Device With Respect to Solar-Hybrid Generating System
Oh, Kyoung Gun ; Moon, Byung Young ; Lee, Ki Yeol ;
Journal of Ocean Engineering and Technology, volume 30, issue 1, 2016, Pages 57~67
DOI : 10.5574/KSOE.2016.30.1.057
As a new technical approach, an attempt was made to realize a photovoltaic system for an eco-environmental leisure ship by simultaneously actuating nine photovoltaic solar panels in association with the application of a sail-controlling system using wind energy. In this approach, the photovoltaic system consisted of a solar module, an inverter, a battery, and the relevant components, while the sail-controlling device was equipped with sail up/down and mast turning systems. The previously mentioned eco-environmental leisure ship utilizes a photovoltaic hybrid system that uses solar and wind energy as renewable energy sources. Furthermore, this research included a performance evaluation of the manufactured prototype, the acquisition of the purposed quantity values, and development of the purposed items. The significant items, including the sail up/down speed (seconds) and mast turning angle (degrees) were evaluated for a performance test. A wind direction sensitivity of 90% and maximum instant charging power of 900 W were also obtained in the process of the performance evaluation. In addition, the maximum sail time was also evaluated in order to acquire the optimum value. The performance evaluation showed that the prototype with a photovoltaic hybrid system was suitable for sailing an eco-environmental leisure ship using solar and wind energy.