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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 22, Issue 6 - Dec 2008
Volume 22, Issue 5 - Oct 2008
Volume 22, Issue 4 - Aug 2008
Volume 22, Issue 3 - Jun 2008
Volume 22, Issue 2 - Apr 2008
Volume 22, Issue 1 - Feb 2008
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Kelvin Ship Wake Modification due to Wind Waves
Lee, Kwi-Joo ; Shugan, I.V. ; An, Jung-Sun ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 1~6
A kinematics model of a ship wake in the presence of surface waves generated by wind is presented. It was found that a stationary wave structure behind a ship covered a wedge region with the angle at the top of the wake and that only divergent waves were present in a ship wake instead of both the longitudinal and cross-waves, which are known as the Kelvin model. Ship motion at some angle to wind waves can cause an essential asymmetry of the wake, compressing its windward half.
Assessment of the Marine Environment in Masan-Jinhae Bay of Korea in Relation to Algal Blooms
Lee, Moon-Ock ; Kim, Pyeong-Joo ; Moon, Jin-Han ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 7~24
Masan-Jinhae Bay, in Korea, is known for its frequent algal bloom outbreaks. This study was conducted in order to examine the environmental characteristics of the area, with the aim of identifying indicators that could be used to speculate about future algal blooms. The water temperatures and salinities in Haengam Bay, one of the small inner bays within Jinhae, appeared to re relatively higher than those in Masan and Jinhae bays, across most seasons. Furthermore, stratification begins to develop in all three regions from spring to summer as a result of the local heating effects and an increase in the efficient from the surrounding land. As a result, anoxic conditions appear near the bottom layer of the bay, leading to the deterioration of water quality, which has been identified as one of the causes of bloom outbreaks. Compared to Haengam and Jinhae bays, concentrations of DIN and DIP were remarkably higher in Masan Bay. However, the mean ratio of DIN to DIP was 3.3
13.6 in all three regions throughout the year, suggesting that nitrogen can function as a growth-limiting factor for phytoplankton. The results of mathematical models showed that cumulative organic pollutants may be a trigger for direct algal bloom occurrences, since residual tidal currents appeared to be less than
. Furthermore, computed DO concentrations in the four small inner bays of Jinhae during the summer appeared to be
indicating a hypoxic state. Likewise, computed Chl-a concentrations turned out to be more than
, indicating eutrophication across most seasons. Based on the overall results, Masan-Jinhae Bay appeared to possess a very high potential for algal bloom outbreaks at anytime during the year.
Application of the B-Spline Based High Order Panel Method to the Floating Body Dynamics
Ahn, Byoung-Kwon ; Lew, Jae-Moon ; Lee, Hyun-Yup ; Lee, Chang-Sup ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 25~30
A B-spline based high order panel method was developed for the motion of bodies in an ideal fluid, either of infinite extent or with a free boundarysurface. In this method, both the geometry and the potential are represented by the B-spline, which guarantees more accurate results than most potential based low order methods. In the present work, we applied this B-spline based high order method to the radiation problem of floating bodies. The boundary condition on the free surface was satisfied by adopting a Kelvin-type Green function and irregular frequencies were removed by placing additional control points on the free surface surrounding the body. The numerical results were validated by comparison with existing numerical and experimental results.
The Simulation of Tsunami against the South Coast of the Korean Peninsula
Kim, Hyun-Seung ; Kim, Hyeon-Seong ; Kang, Young-Seung ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 31~38
The numerical simulation of tsunami against the south coast of the Korean Peninsula has been performed by adopting the standard appropriate grid size and the numerical model has been constructed to include the characteristics of the tsunami propagation applied for the care of the East China Sea. The artificial tsunami has been modelled first and then, it has been used as the boundary condition for the detailed model which showed the south coast of the Korean Peninsula.
An Analytic Solution of the Shape of a Partially Filled, Submerged Membrane Container
Choi, Yoon-Rak ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 39~43
For a partially filled and deeply submersed membrane container, an analytic solution for similarity shape was studied. The static shape of a membrane container can be expressed as a set of nonlinear ordinary differential equations. These equations are combined into an integrable equation. The solution of the equation is derived in terms of elliptic integrals, the arguments of which contain an unknown at the point of inflection. The point of inflection is determined by using the boundary condition at a separating point. Some characteristic values of the similarity shape were evaluated and the shapes are illustrated.
Measurement and Numerical Model for Wave Interation on Impermeable Steep Slopes
Kim, In-Chul ; Ahn, Ik-Seong ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 44~51
The planning and design of coastal structures against wave attack is required to accurately predict wave transformation, wave run-up, and fluid. particlevelocities an a slope. On tire other hand, in tire swash and surf zones of a natural beach, where coastal erosion and accretion occur at tire land-sea boundary, hydrodynamic analysis is essential. In this study, a RBREAK2 numerical model was created based on the nonlinear shallow water equation and laboratory measurements were carried out in terms of tire free surface elevations and velocities for tire cases of regular and irregular waves on 1 : 10 and 1 : 5 impermeable slopes. The data were used to evaluate tire applicability and limitations of tire RBREAK2 numerical model. The numerical mode1 could predict tire cross-shore variation of the wave profile reasonably well, but showed more accurate results for slopes that were steeper than 1 : 10. Except near tire wave crest, tire computed depth averaged velocities could represent tire measured profile below tire trough level fairly well.
Applicability of CADMAS-SURF Code for the Variation of Water Level and Velocity due to Bores
Lee, Kwang-Ho ; Kim, Chang-Hoon ; Hwang, Yong-Tae ; Kim, Do-Sam ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 52~60
This study investigates the applicability of CADMAS-SURF (Super Roller Flume for Computer Aided Design of a MArtime Structure) code basal on the Navier-Stokes solver to predict bore phenomena. The time variation of ware levels and velocities due to the bore propagation were computed for the different bore strength conditions. In order to verify the numerical results by CADMAS-SURF, laboratory experiments were also performed, using the DPIV and LDV measuring system. The numerical results were compared to the experimental data and the analytical predictions by the NSC method basal on fully nonlinear shallow-water theory by the method of characteristics. It appears that the CADMAS-SURF slightly overestimated the water-surface level measured by the laboratory experiments and its discrepancy becomes prominent as the bore strength increases. The predicted propagation speed for a bore was also slaver than that by the experiment and NSC method. However, the temporal variations in velocities were in relatively good agreement with the experimental data for all cases, except for overshooting and undershooting in the front face of a bore, which may be derived from the numerical instability. Further, CADMAS-SURF successfully simulated the decrease in the water level and velocity caused by the effects of negative waves reflected from the upstream end wall.
A Study on the Numerical Model of Current of Strafication Considering the Topographic Heat Accumulation Effect in the Coastal Area
Yoon, Jung-Sung ; Kim, Myoung-Kyu ; Han, Dong-Jing ; Kim, Ga-Ya ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 61~68
In Jinhae-Masan bay, a typical semi-dosed bay in Korea, the water quality is severely deteriorated because of the dosed topographic character and the inflow of nutrients from the land. There have been attempts to apply a water quality model dealing with the entrophication phenomenon and the oxygen-deficient mass in the bay in summer, but there have been few examples of models that have considered the phenomenon of stratification in the proper order, and then it is performed the model of water quality. Therefore, this study collected and analyzed the pre-observed water temperature data from Jinhae-Masan bay in summer and then constructed a density model using the topographic heat accumulation effect and inflow from the river to examine the temperature stratification. The simulation results show that this model could demonstrate the temperature stratification in the Jinhae-Masan bay very well.
Mooring Analysis due to Ship Wave at Gunzang New Port
Kim, Jae-Soo ; Kong, Byung-Seung ; Hong, Nam-Seeg ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 69~74
This study performed a numerical simulation to predict the development of ship waves and their propagation in the shallow water region of Gunzang New Port and to examine the stability of taut line mooring at the sea wall using the design criteria. In order to predict the propagation of ship waves based on the speeds of various ships under complicated and shallow water depths, a computer model was constructed based on the Boussinesque equation with a fixed coordinate system. Additionally, an investigation if the stability was made by applying MOSES under the environmental loadings estimated by OCIMF.
Numerical Prediction for Reduction of Oxygen Deficient Water Mass by Ecological Model in Jinhae Bay
Lee, In-Cheol ; Kong, Hwa-Hun ; Yoon, Seok-Jin ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 75~82
As a basic study for establishing a countermeasure for an oxygen deficient water mass (ODW), we investigated the variation of ODW volume according to the enforced total pollution load management in Jinhae Bay. This study estimated the inflowing pollutant loads into Jinhae Bay and predicted the reduction in ODW by using a sediment-water ecological model (SWEM). The result obtained in this study are summarized as follows: 1) The daily average pollutant loads of COD, SS, TN, TP, DIN, and DIP inflowing into Jinhae bay in 2005 were estimated to be about 12,218 kg-COD/day, 91,884 kg-SS/day, 5,292 kg-TN/day, 182 kg-TP/day, 4,236 kg-DIN/day, and 130 kg-DIP/day. 2) The calculated results of the tidal current by the hydrodynamic model showed good agreement with the observed currents. Also, an ecological model well reproduced the spatial distribution of the water quality in the bay. 3) This study defined the ODWDI (ODW decreasing index) in order to estimate the ODW decreasing volume caused by a reduction in the inflowing pollutant loads. As a result, the ODWDI was predicted to be about 0.91 (COD 30% reduction), 0.87 (COD 50% reduction), 0.79 (COD 70% reduction), 0.85 (ALL 30% reduction), 0.66 (ALL 50% reduction), and 0.45 (ALL 70% reduction). The ODW volume was decreased 1.5
2.6 times with a reduction in the COD, TN, and TP inflowing pollutant loads compared to a reduction in just the COD inflowing pollutant load. Therefore, it is necessary to enforce total pollution load management, not only for COD, but also fm TN and TP.
Study on Resistance of Icebreaker by Density Variation of Synthetic Ice in General Towing Tank
Lim, Tae-Wook ; Kim, Moon-Chan ; Chun, Ho-Hwan ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 83~86
This paper deals with the experimental works for the correlations of ice resistance for icebreaker with synthetic(model) ice in general towing tank and with refrigerated ice in ice tank. In order to find out the correlation, the density variation is mainly focused in the present study. The model of Terry-Fox ice breaker has been used for the present correlation study because many data are available to be compared. According to the increase of density, the correlation becomes better quantitatively as well as qualitatively. Other parametric studies such as an ice size, a friction coefficient, a bending moment, etc., are also expected to be carried out to have better correlation in a near future. This research could be the basis for the possibility of resistance test using a synthetic ice in a general towing tank instead of an expensive ice tank.
A Study on Statistical Properties of Vickers Hardness of Friction Welded Parts in Alloy718 Steel (Part 1. As-welded)
Kwon, Hyeok-Yong ; Choi, Sung-Yoong ; Lee, Sang-Yeal ; Kong, Yu-Sik ; Kim, Seon-Jin ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 87~93
The objective of this paper is the investigation of the statistical properties of Vickers hardness (HV) of friction welded parts in nickel based super resisting steel, alloy 718 steel. First, we examine the statistical properties on the case of as-welded parts. Several Virkers indentations were made under same nominal conditions. This was repeated for three different applied loads, 100, 200 and 300g with a duration time, 10 second. The arithmetic mean of Vickers hardness in base metal (BM) materials is larger than that of HAZ in all applied loads. The measure of dispersion, that is, the coefficient of variation (COV) for BM and HAZ is decreased by increasing with the applied load. The distribution of Vickers hardness was not found to be symmetric type. The probability distribution of Vickers hardness was well followed Weibull distribution. The shape parameter and the scale parameter (characteristic hardness) are increased by increasing with the applied load, as both BM and HAZ.
Study of Application of Salt Resistance Concrete Beam Reinforced with Glass Fiber Reinforced Polymer-Ribbed Bar as a Member of Marine Structure
Kim, Chung-Ho ; Hwang, Yun-Hee ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 94~99
Three types of salt resistant concrete beams reinforced with glass fiber reinforced polymer-ribbed bars (GFRP-ribbed bars) were selected, and their applicable properties were investigated with the goal of improving the problem of capacity deterioration in marine structures due to sea water corrosion. In this study, the structural behaviors were similar to RC beams in relation to the development of the strength and stiffness up to the generation of the initial crack. After the growth of this initial crack, the structural properties decreased owing to a sudden loss of bond strength. Also these beams showed the trends of brittle failure. As a result, it was confirmed that a GFS beam replaced with Fly Ash (20%) and Silica Fume (5%) has the best application as a marine structural element.
Evaluation on Corrosion of A106 Carbon Steel using AE Technique
Lee, Jin-Kyung ; Lee, Sang-Pill ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 100~105
A106 Carbon Steel has recently been used as the material for pipes, nozzles, and tank shells in nuclear power plants. Its corrosion resistance gives the steel many advantages for use in structures under high temperature and high pressure. This steel is also expected to be used as a structural material in the shipbuilding industry for applications involving severe conditions, such as high temperature and pressure. In this study, the mechanical properties of A106 carbon steel were evaluated in regard to its corrosion times. The tensile and yielding strengths decreased as the corrosion time increased. In particular, the tensile strength was influenced by corrosion. In addition, an acoustic emission (AE) technique was used to clarify the microscopic damage to specimens that had undergone corrosion for a certain period. It was found that AE parameters, such as events, energy, duration time, and amplitude were useful for evaluating the degree of damage and remaining life of the corroded specimen. Various properties of the waveform and frequency range were also seen, based on the degree of damage to the specimen from the corrosion time.
Fabrication and Wear Property Evaluation for FeCrSi/AC8A Composite by Low-pressure Infiltration
Song, Tae-Hoon ; Lee, Hyun-Jun ; Choi, Yong-Bum ; Kim, Sung-Jin ; Park, Won-Jo ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 106~111
In this paper, study about property evaluation for the metal matrix composites fabricated by low pressure infiltration process. Aluminum alloy composite which is reinforced by Metal fiber preform was fabricated by low pressure casting process. Infiltration condition was changed the pressure infiltration time of 1 sec, 2 sec and 5 sec under a constant pressure of 0.4 MPa. The molten alloy completely infiltrated the FeCrSi metal perform regardless of the increase in the pressure acceleration time. The the porosity in the FeCrSi/AC8A composite was investigated. The porosity was reduced as the pressure acceleration time as shorter. The FeCrSi/AC8A composite was investigated the wear test for to know the relationship between Porosity and wear resistance. FeCrSi/AC8A composite at pressure acceleration time of 1sec is shown excellent wear resistance.
Experimental Study of Waste Tire Powder-Added Lightweight Soil as Flowable Backfill
Kim, Yun-Tae ; Kang, Hyo-Sub ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 112~118
The purpose of this study was to determine the engineering and environmental properties of the waste tire powder-added lightweight soil (TLS) used as flowable backfill. The TLS used in this experiment consisted of dredged soil, bottom ash, waste tire powder and cement. Test specimens were prepared with various contents of waste tire powder ranging from 0% to 100% at 25% intervals and water contents ranging from 140% to 200% by the weight of the dry dredged soil. Several series of unconfined compression tests, flow tests, and leaching tests were carried out. Experimental results for the TLS indicated that the unconfined compressive strength, secant modulus (), and unit weight of the TLS decreased with an increase in waste tire powder content. However, as the waste tire powder content increased, the stress-strain relationship of the TLS showed more ductile behavior rather than brittle behavior. The flow value increased with an increase in water content, but decreased with an increase in waste tire powder content. The result of the leaching test showed that the leaching amounts of heavy metals were lower than the permitted limits suggested by the Ministry of Environment.
A Study of Musculoskeletal Disorders Reduction Scheme in Shipbuilding Process Using 3D Human Simulation
Min, Kyong-Cheol ; Kim, Dong-Joon ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 119~125
Musculoskeletal disorders(MSDs) are one of the major issues in shipbuilding industry. Main risk factors of MSDs include manual handling of heavy weight, awkward posture, repetitive tasks, prolonged static muscle contraction, and so on. in this study, Using the three-dimensional digital human modeling and simulation method we made up a worker and work posture on a virtual environment. To verify this simulation we compared both traditional ergonomic analysis on a real worker and digital program analysis on a digital human. And this paper shows that it is possible to reduce the rate of MSDs in the shipbuilding industry because it means we can change poor posture mid surroundings into better ones.
New Scheme for Intelligent Voyage Data Recorder Analysis System and Development of Visualization Module of the VDR
Hwang, Il-Kyu ; Lee, Kyung-Ho ; Han, Young-Soo ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 126~131
The voyage data is very important for safety of ships, and duty being effectuated by the installation of voyage data record (VDR) on ships. VDR is a black-box, and it contains 14 kinds of voyage data as text. But it is not easy to understand when the accident happened because voyage data is saved as complicated texts. User interface (UI), analysis, visualization system, which works for assist to gather information about situation of accident, was developed. It will be possible to develop onboard ship monitoring and voyage prediction system by the VDR visualization system's development in near future.
The Development of Design Formulas for Pipe Loops Used in Large Vessels (I)
Park, Chi-Mo ; Yang, Park-Dal-Chi ; Lee, Jong-Hoon ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 132~137
Ship structures are subject to severe environmental loads causing appreciable hull girder bending which in turn affects the piping system attached to the main hull in the form of a displacement load. While this load may cause failure in the pipes, loops have been widely adopted as a means of preventing this failure, with the idea that they may lower the stress level in a pipe by absorbing some portion of the displacement load. But since such 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 the loops adopted need to be minimized. This research developed design formulas for pipe loops, modeling them as frames composed of beam elements, where not only bending but also shear deflection is taken into account. The accuracy of the proposed design formulas was verified by comparing two results respectively obtained by the proposed formulas and MSC/NASTRAN. The paper concludes with a sample example showing the efficiency of the proposed formulas.
Development of Deep Draught Semisubmersible Shape
Lee, Jin-Ho ; Lee, June-Young ; Kim, Byung-Woo ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 138~141
This paper treats the development of a new type of deep draught semisubmersible offshore structural shape that has excellent heave motion response and less down-time. This new type of semisubmersible shape is characterized by heave dampers at each pontoon corner and appropriate column size adjustment to achieve the desired cancellation and resonance motion period. It was found that the final model had efficient workability, based on the wavescatter diagrams for the GoM and North Atlantic ocean, due to less heave motion, although the specific heave response at the 100 year return period wave condition in the North Atlantic was more or less increased.
Analysis of New Health Monitoring System for Long Span Bridge over the Sea
Kong, Byung-Seung ;
Journal of Ocean Engineering and Technology, volume 22, issue 5, 2008, Pages 142~147
The cases of using new methods of big blocks are largely increasing on Recent large-scale bridge structures. So the accurate data of responses of bridges following environmental causes are required to be quickly recorded in order to predict. For this reason described above, the research on measuring system should be conducted for more knowledge of the details on application and stability of new methods. In this study, the new health monitoring system that can monitor the real behavior and damages of the bridge during all processes of construction is presented by analyzing cases of domestic and overseas bridge health monitoring system, and applied methods of following bridges.