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 23, Issue 6 - Dec 2009
Volume 23, Issue 5 - Oct 2009
Volume 23, Issue 4 - Aug 2009
Volume 23, Issue 3 - Jun 2009
Volume 23, Issue 2 - Apr 2009
Volume 23, Issue 1 - Feb 2009
Selecting the target year
Mooring Cost Sensitivity Study Based on Cost-Optimum Mooring Design
Ryu, Sam Sangsoo ; Heyl, Caspar ; Duggal, Arun ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 1~6
The paper describes results of a sensitivity study on an optimum mooring cost as a function of safety factor and allowable maximum offset of the offshore floating structure by finding the anchor leg component size and the declination angle. A harmony search (HS) based mooring optimization program was developed to conduct the study. This mooring optimization model was integrated with a frequency-domain global motion analysis program to assess both cost and design constraints of the mooring system. To find a trend of anchor leg system cost for the proposed sensitivity study, optimum costs after a certain number of improvisation were found and compared. For a case study a turret-moored FPSO with 3
3 anchor leg system was considered. To better guide search for the optimum cost, three different penalty functions were applied. The results show that the presented HS-based cost-optimum offshore mooring design tool can be used to find optimum mooring design values such as declination angle and horizontal end point separation as well as a cost-optimum mooring system in case either the allowable maximum offset or factor of safety varies.
A Study on Effect of Beachface Gradient on 3-D Currents around the Open Inlet of Submerged Breakwaters
Lee, Woo-Dong ; Hur, Dong-Soo ; Park, Jong-Bae ; An, Sung-Wook ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 7~15
The aim of this study was to survey the effects of the beachface gradient on 3-D currents around the open inlets of submerged breakwaters. First, the numerical model was validated by a comparison with existing experimental data. This model is able to consider the flow through a porous medium with inertial, laminar, and turbulent resistance terms, i.e. simulate directly WAve?Structure?Seabed/Sandy beach interaction, and can determine the eddy viscosity with a LES turbulent model in a 3-Dimensional wave field (LES-WASS-3D). Using the numerical results of this model, the 3-D currents around the open inlets of submerged breakwaters were examined in relation to the beachface gradient. Moreover, the wave height distribution and mean flow around them are also discussed, as well as the distribution of the wave breaking points over the crest.
Time Domain Analysis of Ship Motion in Waves Using Finite Element Method
Nam, Bo-Woo ; Sung, Hong-Gun ; Hong, Sa-Young ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 16~23
The three-dimensional ship motion with forward speed was solved by a finite element method in the time domain. A boundary value problem was described in the frame of a fixed-body reference, and the problem was formulated according to Double-Body and Neumann-Kelvin linearizations. Laplace's equation with boundary conditions was solved by a classical finite element method based on the weak formulation. Chebyshev filtering was used to get rid of an unwanted saw-tooth wave and a wave damping zone was adopted to impose a numerical radiation condition. The time marching of the free surface was performed by the 4th order Adams-Bashforth-Moulton method. Wigley I and Wigely III models were considered for numerical validation. The hydrodynamic coefficients and wave exciting forces were validated by a comparison with experimental data and the numerical results of the Wigley I. The effects of the linearization are also discussed. The motion RAO was also checked with a Wigley III model through mono-chromatic and multi-chromatic regular waves.
A Study on the Pollution Risk Assessment of Oil Spill Accidents
Lee, Moon-Jin ; Kim, Hye-Jin ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 24~30
The purpose of this study was to establish an assessment method for the estimation of the pollution risk by oil spill accidents. Various oil spill patterns were calculated based on past accidents in the study area and these results were analyzed statistically. Then the risk probability, the oil arrival time, risk range, and so on were calculated. These calculations were performed for sub area sectors, fisheries and aquaculture farms, based on information about environmentally sensitive resources. Finally, the risk to each sub area sector was assessed by comparing the calculated results. These consequences indicated the objective and general risks of oil spill accidents and the result of this method will be made more appropriate by integrating real time risk predictions.
Hydraulic Experiment on the Effects of Beach Erosion Prevention with Flexible Coastal Vegetation
Lee, Seong-Dae ; Park, Jung-Chul ; Hong, Chang-Bae ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 31~37
Coastal vegetation consists of rooted flowering marine plants that provide a variety of ecosystem services to the coastal areas they colonize. The attenuation of currents and waves and sediment stabilization are often listed among these services. From this point of view, artificial seaweed is an effective method of controlling sea bed sediment and stabilization without damaging the landscape or the stability of the coastline. A series of hydraulic experiments were performed in a wave channel with regular and irregular waves to examine the effect of artificial seaweed in relation to scouring and beach erosion prevention. Based on the results of these experiments, the coastal vegetation model is efficient against scouring and beach erosion.
Development of Rendering Techniques for Particle-based Flow Simulation
Lee, Byung-Hyuk ; Park, Jong-Chun ; Jang, Young-Su ; Kim, Sang-Hyun ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 38~42
Recently, various particle based simulation techniques, which solve the Navier Stokes and continuity equations, have been developed and applied to complicated engineering problems. However, although progress is being made on their visualization or rendering techniques, these are still insufficient. In this study, to render a smooth configuration for a free surface, a rendering technique was developed that included the generation of density fields from the location information for simulated particles and the creation model for a polygonal surface. The developed rendering technique was applied to the visualization of a dynamic free surface flow interacting with a structure using a particle based simulation technique.
A Study on Flow Structure of Breaking Wave through PIV Analysis
Jo, Hyo-Jae ; Lee, Eon-Ju ; Doh, Deog-Hee ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 43~47
This paper compares theoretical wave profile and particle kinematics with experimental results generated by a 2 D wave tank. Particle velocity fields of compound waves were acquired using a PIV technique. Synchronization was applied to acquire images of the wave fields, and the time gap between these images was controlled by the user. This technique was applied to investigate the wave breaking mechanism, and the wave profile and velocity distribution in a wave breaking field was obtained.
A Study on the Motion Analysis and Design Optimization of a Ducted Type AUV (Autonomous Underwater Vehicle) by Using CFD (Computational Fluid Dynamics) Analysis
Joung, Tae-Hwan ; Sammut, Karl ; He, Fangpo ; Lee, Seung-Keon ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 48~53
Autonomous Underwater Vehicles (AUV's) provide an important means for collecting detailed scientific information from the ocean depths. The hull resistance of an AUV is an important factor in determining the power requirements and range of the vehicle. This paper describes a design method that uses Computational Fluid Dynamics (CFD) to determine the hull resistance of an AUV under development. The CFD results reveal the distribution of the hydrodynamic values (velocity, pressure, etc.) of an AUV with a ducted propeller. This paper also discusses the optimization of the AUV hull profile to reduce the total resistance. This paper demonstrates that shape optimization in a conceptual design is possible by using a commercial CFD package. Optimum design work to minimize the drag force of an AUV was carried out, for a given object function and constraints.
Structual Stability Analysis According to the Lumped Mass of High Speed Vehicles in Underwater
Oh, Kyung-Won ; Sur, Joo-No ; Cho, Byung-Gu ; Ryu, Si-Ung ; Kong, Gong-Duk ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 54~59
In this paper, the effect of the position and size of a lumped mass on the structural stability of a high speed underwater vehicle is presented. For simplicity, a real vehicle was modeled as a follower force subjected beam that was resting on an elastic foundation, and the lumped mass effect was simplified as an elastic intermediate support. The stability of the simplified model was numerically analyzed based on the Finite element method (FEM). This numerical simulation revealed that flutter type instability or divergence type instability occurs, depending on the position and stiffness of the elastic intermediate support, which implies that the instability of the real model is affected by the position and size of the lumped mass.
An Experimental Study on Shallow Water Effect in Slamming
Kang, Hyo-Dong ; Oh, Seung-Hoon ; Kwon, Sun-Hong ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 60~66
This study presents an experimental investigation of the shallow water impact of a box type structure. The analysis was done based on the video images captured by a high speed camera, the flow field obtained by PIV (Particle Image Velocimetry), and pressure measurements in the divided region. The video images showed quite good agreement with the description given by Korobkin. The PIV measurements of the velocity field provided a clear view of the flow pattern for all three stages. The pressure was measured at the bottom of the tank with strain gauge type pressure gauges. The pressure measurements showed the characteristics of divided regions.
A Study on Slamming Impact Pressure
Park, Jun-Soo ; Oh, Seung-Hoon ; Kwon, Sun-Hong ; Chung, Jang-Young ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 67~73
This study presents the results of a slamming experiment using a pneumatic cylinder. The employment of the pneumatic cylinder showed a relatively good repeatability when the results were compared with those of other slamming devices. The experiment was done for various incident angles. An air pocket was believed to cause a reduction in the magnitude of the impact pressure with an incident angle of
for the water entry. A high speed camera was used in an attempt to locate the time of the contact between the bottom of the specimen and the free surface. It seemed that the maximum pressure occurred before the water contacted the bottom of the specimen.
Study on Eigenvalue Analysis for a Towed Cable - Free Boundary at the Bottom End
Jung, Dong-Ho ; Kim, Hyeon-Ju ; Moon, Deok-Soo ; Lee, Seung-Won ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 74~80
In this study, the static and modal analyses to find the characteristic of eigenvalues for a towed cable were with a free boundary condition at the bottom end carried out with numerical study. The resulting numerical code with finite element method was used to study sample problems for a cable with towing speeds. After tracing the equilibrium state with a towing speed through the static analysis, modal analysis on the basis of static results was performed. The static top tension for a critical towing speed is nearly 50 percent of what it was for a free hanging pipe. From static analyses, it is found that towing speed has a noticeable effect on top tension of a towed pipe. At a high towing speed, differences between the first and second periods become larger. Compared to the fundamental period for a free hanging pipe, that for a towed pipe with a critical towing speed is approximately 1.4 times larger. This result is very important point in that the lock in condition and tension of the towed cable system with top excitation can be predicted. The corrected close form solution to solve natural periods for a towed cable was presented in this study. The code is validated by comparison of the results of theoretical and numerical studies. Two results were in very good agreement. This study can contribute to predicting the lock-in condition and tension for a towed cable or pipe with top excitation.
Design of Oceanography Buoy - Part I: Structural Integrity of Hull
Kim, Tae-Woo ; Keum, Dong-Min ; Han, Dae-Suk ; Lee, Won-Boo ; Lee, Jae-Myung ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 81~88
An evaluation of the structural integrity of an oceanographic buoy subjected to extreme loads was carried out in this study. Load components, such as the current, waves, and wind load, which were required for the sea's environmental conditions, were calculated precisely. A non linear finite element analysis was conducted to elucidate the structural response of the buoy under extreme environmental conditions. Based on the surface drift velocity scheme, a dynamic impact analysis was also carried out for the case of collision accidents. The proposed numerical technique would be a useful and cost effective tool for design scheme evaluation in the field of oceanographic buoys.
Design of Oceanography Buoy - Part II: Mooring System
Keum, Dong-Min ; Kim, Tae-Woo ; Han, Dae-Suk ; Lee, Won-Boo ; Lee, Jae-Myung ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 89~95
The purpose of the present study was to evaluate the safety under extreme environmental conditions and the dynamic safety under service environment conditions, of oceanographic buoy mooring systems consisting of a variety of materials, including chain, wire rope, nylon rope, and polypropylene rope. For the static safety assessment of a mooring system, after the calculation of external forces and the division of a mooring system into finite elements, the numerical integral was conducted to yield the elemental static tension until satisfying the geometrical convergence condition. To evaluate the dynamic safety, various processes were considered, including data collection about the anticipated areas for mooring, a determination of the parameters for the interpretation, the interpretation of the dynamic characteristics based on an analytic equation that takes into account the heave motion effect of a buoy hull and a mooring system, and a fatigue analysis of the linear cumulative damage. Based on the analysis results, a supplementary proposal for a wire rope that has a fracture in an actual mooring area was established.
Numerical Simulation of Arch-type Submarine Cable Protector under Anchor Collision
Woo, Jin-Ho ; Na, Won-Bae ; Kim, Heon-Tae ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 96~103
In 2006, Jeju Island in South Korea experienced a crisis, no electricity for three hours anywhere in the entire island. This incident was caused by a domino effect that occurred after one of the submarine power cables connecting the island to Haenam, a coastal city on the mainland, was damaged by an external load, probably from a ship anchor or a steel pile being used in marine farming. This study presents a collision analysis of a new submarine power cable protector called arch type reinforced concrete. For the analysis, a dynamic finite element program, ANSYS AUTODYN, was used to examine the displacement and stress of the submarine power cable protector using different material models (RHT concrete model, Mohr.Coulomb concrete model). In addition, two reinforcing bar spacings, 75 mm and 150 mm, were considered. From the analyses, the effects of the parameters (concrete model and spacing) on the results (displacement and stress) were analyzed, and the relations between the damage and parameters were found.
Dynamic Stability during Transportation of Bridge Caisson
Jo, Chul-Hee ; Kim, Sung-Jun ; Cheong, Hyun ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 104~108
As the demands of ocean resource development increase, many offshore structures are required. To cope with the active ocean developments, many types of construction methods have been applied for offshore facilities, including oil, gas and harbors. One of the challenges is to transport and install the heave bridge caisson. Several construction methods are well understood. However, for the sake of safety and reliability, the F/D installation method can be utilized. While the caisson is carried by an F/D, the mooring force of the tug boat and the structure stability from exiting motions in the dock should be checked against external loadings and sea conditions. The external loads can be classified with wind force, current force, and wave force. In the stability analysis, transportation velocity and draft of F/D are important factors. The dynamic stability and hook load for crane barge installation for the same caisson are also studied. Considering external loads and dominant factors, the stability of caisson during transportation has been investigated.
Ocean Current Power Farm Interaction Study
Jo, Chul-Hee ; Yim, Jin-Young ; Chae, Kwang-Su ; Park, Ro-Sik ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 109~113
Several tidal current power plants are being planned and constructed in Korea utilizing the strong tidal currents along the west and south coasts. A tidal current reaches 9.7 m on the west coast; there are few potential regions for tidal current power generation. The construction of a dam to store water can prevent the circulation of water, causing a great environmental impact on the coast and estuary. The tidal barrage could produce a large amount of power, but it should be carefully considered. The purpose of developing renewable energies is to minimize the environmental impact and to maximize the utilization of clean energy. To produce a great quantity of power, tidal current farms require the placement of numerous units in the ocean. The power generation is very dependent on the size of the rotor and the incoming flow velocity. Also, the interactions between devices contribute greatly to the production of power. The efficiency of a power farm is estimated to determine the production rate. This paper introduces 3 D interaction problems between rotating rotors, considering the axial, transverse, and diagonal distances between horizontal axis tidal current devices.
Dynamic Response Analysis of Caisson Structure by Acceleration Measurement
Lee, So-Young ; Kim, Jeong-Tae ; Kim, Heon-Tae ; Park, Woo-Sun ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 114~121
In this study, acceleration responses of caisson structures under various environmental conditions are experimentally examined as a basic study to develop the health assessment technique for harbor structures. To achieve the objective, three approaches are implemented. Firstly, a target caisson structure is selected and its small-scaled caisson is constructed in the laboratory. Secondly, a finite element model of the caisson is generated to identify dynamic responses of the baseline structure. Thirdly, experimental tests are performed on the caisson model to examine dynamic responses under various boundary conditions and impact locations. Four different boundary conditions, 'standing on concrete floor', 'standing on styrofoam block', 'standing on sand-mat' and 'hanging by crane', are considered and correlation coefficients of frequency response functions between four states are analyzed.
Structural Health Monitoring of Harbor Caisson-type Structures using Harmony Search Method
Lee, So-Young ; Kim, Jeong-Tae ; Yi, Jin-Hak ; Kang, Yoon-Koo ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 122~128
In this study, damage detection method using harmony search method and frequency response is proposed. In order to verify this method, the following approaches are implemented. Firstly, damage detection method using harmony search was developed. To detect damage, objective functions that minimize difference with natural frequency and modal strain energy from undamaged and damaged model are used. Secondly, efficiency of developed damage detection method was verified by damage detection of beam structure. And results of harmony search and micro genetic algorithm are compared and evaluated. Thirdly, numerical model was implemented for harbor caisson structure and damage scenario was determined. Lastly, damage detection was performed by proposed method and utility of proposed method is verified.
Comparison Study on the Propulsion Performance for Icebreaker with Synthetic ice and Refrigerated ice
Kim, Moon-Chan ; Lim, Tae-Wook ; Jo, Jun-Cheol ; Chun, Ho-Hwan ; Wang, Jung-Yong ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 129~134
This paper reports on experimental investigations of self propulsion performance with synthetic (model) ice and refrigerated ice, which were conducted in a typical towing tank and ice tank, respectively. The main purpose of this research was to find the correlation between the selfpropulsion performance with synthetic ice in a typical towing tank and that with refrigerated ice in an ice tank. The different stresses between the synthetic ice and refrigerated ice influenced the self propulsion performance due to different ice and propeller interactions. A further study on the ice property variation for a self propulsion performance comparison is to be conducted in the near future.
A Study on the In-line Assessment of Completion for Fabrication of Curved Plates(I)
Jung, Jae-Min ; Park, Chi-Mo ; Yang, Park-Dal-Chi ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 135~139
In the line heating for the plate forming of a ship's hull, an in line assessment of completion is necessary for an automated production system. In the current curved plate forming process, a fabricated plate is compared to a template that is made in the mold loft and is used for the determination of the heating line for the next step. In this paper, a new method is presented for the in line assessment of completion for curved plate forming. This method uses a 3-D scanner. For the registration of the scanned data for a surface and the target surface, the ICP (Iterative Closest Points) method was adopted. A computer program was developed to carry out the registration, check for similarities, visualize the surface, and control the results. This program was applied to a sample curved plate forming process.
Structural Analysis of 1000A Butterfly Valve Components
Kong, Yu-Sik ; Kim, Seon-Jin ; Jung, Min-Hwa ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 140~145
This paper deals with a stability evaluation of a butterfly valve using the body and disc of a valve seat. The experimental results of a strength evaluation are shown using STS316 stainless steel and spheroidal graphite cast iron (GCD450). The disc material was made from GCD450. The results of the strength analysis are as follows: Ultimate tensile strength 485MPa, Yield strength 370 MPa, Young's modulus
, and Poisson's ratio v = 0.28. For the results of the disc analysis, the safety factor was about 4. This shows that a design was derived that satisfied the requirements of structural safety. However, some problems, such as the deflection and deformation of the disc, may occur when the sea water has back flow with a high pressure.
Weight Function Theory for a Mode III Crack In a Rectilinear Anisotropic Material
An, Deuk-Man ; Kwon, Sun-Hong ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 146~151
In this paper, a weight function theory for the calculation of the mode III stress intensity factor in a rectilinear anisotropic body is formulated. This formulation employs Lekhnitskii's formalism for two dimensional anisotropic materials. To illustrate the method used for the weight function theory, we calculated the mode III stress intensity factor in a single edge-notched configuration.
Development of a Digital Mock-up for Conceptual Design of a Submarine
Kim, Tae-Hwan ; Chun, Sang-Hoo ; Sheen, Dong-Mok ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 152~157
In designing and manufacturing a submarine, an expensive real mock up is usually built as a reference because of the spatial constraints of a submarine. This paper presents an integrated and automated design process for a submarine that uses a digital mock up. Various equipment libraries are built for feature based design. Using the developed digital mock up, this paper shows various ways to verify the design, including a space analysis to check for any interference between pieces of equipment and the hull and an ergonomic analysis using lifelike dummies to examine the work space and operability. As a part of the integrated design system, a design automation system was also developed to generate surface point data for the outer hull, pressure hull, casing, and sail. The whole process was applied to the design of a submarine for verification.
The Development of Design Formulas for Pipe Loops Used in Large Vessels(II)
Park, Chi-Mo ; Yang, Park-Dal-Chi ; Lee, Jong-Hoon ;
Journal of Ocean Engineering and Technology, volume 23, issue 1, 2009, Pages 158~163
Many longitudinal pipes in ships are subject to considerable loads, caused by hull girder bending in the ships and/or thermal loads in some special pipes through which fluids with highly abnormal temperatures are conveyed. As these loads may cause failure in the pipes or their supporting structures, loops have been widely adopted to prevent such failure, based on the idea that they can lower the stress level in a pipe byabsorbing some portion of these loads. But as the loops also have some negative effects, such as causing extra manufacturing cost, deteriorating the function of the pipe, and occupying extra space, the number and dimensions of these loops need to be minimized. This research developed design formulas for pipe loops, modeling them as a spring element, for which the axial stiffness is calculated based on the beam theory, incorporating the flexibility effect of the straight portion of the pipe. The accuracy of the proposed design formulas was verified by comparing two results obtained from the proposed formulas and MSC/NASTRAN. This paper concludes with a sample application of the proposed formulas, showing their efficiency.