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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
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Volume & Issues
Volume 10, Issue 4 - Nov 1996
Volume 10, Issue 3 - Aug 1996
Volume 10, Issue 2 - May 1996
Volume 10, Issue 1 - Feb 1996
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On the Characteristics of Still-Water and Wave Bending Moments with the Variations of Ship Weight Distribution
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 3~13
An extensive research programme has been aimed at the effct of ship weight distribution on the ship responses applying ship hydroelasticity theory. In the previous works, consistent tendencies of the still-water and the wave bending moments. respectively, were found as the weight distribution was varied systematically. The paper is therefore concerned mainly with any correlation between still-water and wave bending moments with the variations of weight distribution. Although these bending moments share different features with each other, such a comparison of tendencies was plausible and informative. These and other matters for the future are discussed.
A Study on Corrosion Fatigue Properties of Welded Joints for TMCP High Strength Steels
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 14~23
The corrosion fatigue test were carried out to evaluate the fatigue characteristics of accelerated cooled (ACC) TMCP high tensile strength steels and weld joint with high heat input by one side one run submerged are welding. In this paper, the fatigue crack growth behaviors were investigated with the center crack tension specimen of base metal and heat affected zone in substitute sea water and air, respectively Main results obtained are sunnarized as follows: 1. The fatigue crack growth rates in sea water faster than those in air environment for the different heat input values, crack growth rate of base metal is very fast and effect of heat input is not remarkable. 2. In HAZ (82kJ/cm, 116kJ/cm), the crack branching phenomena were observed in both air and sea water environment, 3. In SEM observation, the corrosion effect on base metal was larger than that on HAZ in corrosion environment.
Optimization of Bar-to-Bar Dissimilar Friction Welding of Hydraulic Valve Spool Steel and the Weld Strength Properties and Its AE Evaluation
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 24~33
Up to now, most of studies on mechanical properties in friction welded components are about tensile and bending strength. However the fatigue studies on the friction-welded components subjected to repeated stress are not available. The purposes of this study are the development of fundamental design and the development of in-process real-time weld quality evaluation technique by acoustic emission for the bar-to-bar dissimilar friction welding of hydraulic valve spool steels.
The Planar Orientation of Fibers During Compression Molding of Short-Fiber Reinforced Polymeric Composites
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 34~43
In this study basic equations of fiber orientations is cimpared with experimental results. It is found that fiber orientations of short fiber reinforced polymeric composite under compression molding are governed by slope of flow speed in x-y direction. Fiber orientation angle of mold is also found to increase with closure speed and the compression ratio. At the middle of the mold, the slope of flow speed is larger in x-direction than in y-direction. At the wall of the mold, the shope of flow speed in y-direction occurs due to the effect of friction, hence affects the fiber orientation. The effect of partial flow, which incurs y-direction orientation causes to increase the fiber orientation angle at the fore part of the flow.
Numerical Computation of Turbulent Flow over a Backward Facing Step
Van, Suak-Ho ;
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 44~49
Computational Study on the Characteristics of Nonlinear Wave Caused by Breaking Waves of Two-Dimensional Regular Periodic Wave
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 50~61
The breaking phenomenon of regular periodic waves generated by a numerical wave maker is simulated by finite-difference method which can cope with strong interface motions. The air and water flows are simultaneously solved in the time-marching solution procedure for the Navier-Stokes equation. A density-function technique is devised for the implemenation of the interface conditions. The accuracy is examined and applied to the simulation of two-dimensional breaking phenomena of periodic gravity waves.
Numerical Analysis of the Three-Dimensional Nonlinear Waves Caused by Breaking Waves around a Floating Offshore Structure
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 62~73
Numerical simulation is made of the three-dimensional wave breaking motion about a part of a floating offshore structure containing a circular cylinder mounted vertically onto a lower hull in regular periodic gravity wave generated by a numerical wave maker. TUMMAC-VIII finite-difference method is newly developed for such a problem. By use of density-function technique the three-dimensional wave breaking motion is approximately implenented in the framework of rectangular grid system. A porosity technique is devised for the implementation of the no-slip bydy boundary conditions. The generation of breaking waves by the interaction of incident waves with the structure is well simulated and interesting features of breaking waves are revealed with containing degree of quantitative and qualitative accuracy.
On the Negative Drift Force Acting on a Freely Floating Surface-Piercing Cylinder
Hong, Do-Chun ;
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 74~82
Experimental Study of Flow Fields around Cylinder Arrays Using PIV
Jeon, Wan-Soo ;
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 83~88
Flow Field Analysis around Multi-Cylinders Using Particle Image Velocimetry
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 89~95
The flow field around four cylinders for various angles was investigated utilizing particle image velocimetry(PIV) technique. Flow field was recorded by video camera first. Then application of PIV technique was done to the flow field. The results turned out to be useful to analyze complex flow field around multiple cylinders.
Hamilton제s Principle for the Free Surface Waves of Finite Depth
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 96~104
Hamilton's principle is used to derive Euler-Lagrange equations for free surface flow problems of incompressible ideal fluid. The velocity field is chosen to satisfy the continuity equation a priori. This approach results in a hierarchial set of governing equations consist of two evolution equations with respect to two canonical variables and corresponding boundary value problems. The free surface elevation and the Lagrange's multiplier are the canonical variables in Hamilton's sense. This Lagrange's multiplier is a velocity potential defined on the free surface. Energy is conserved as a consequence of the Hamiltonian structure. These equations can be applied to waves in water of finite depth including generalization of Hamilton's equations given by Miles and Salmon.
Unsteady Flow in a Cavity Induced by An Oscillatory External Flow
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 105~116
In this paper, we report the experimental results for the flow pattern and the material transport around a cavity subject to a sinusoidal external flow at the far region to ward the open side of the cavity. A tilting mechanism is used to generate a oscillatory flow inside a shallow rectangular container having a cavity at one side. The surface flow visualization is performed to obtain the unsteady behavior of vortices generated at two edges situated at the entrance of the cavity. It was found that at the period 4.5 sec., the behavior of the vortices is asymmetric, and there exists a steady residual flow in the cavity. The bottom flow patterns are also visualized. There are two regions outside of the cavity where the bottom fluid particles concentrate. The material transport in this flow model is very peculiar; fluid particles in the cavity flows outward through the passage along the walls starting from the edges, and particles in the outer region approach the cavity from the central region.
A Study on the Flow Characteristics of Bubbles in a Fluidized Bed
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 117~124
A fluidized bed combustion chamber is widely used to incinerate waste material. The most important factor designing the incinerator is the flow characteristics in a fluidized bed, because combustion efficiency is influenced by the flow characteristics. This paper has invesitigated the flow characteristics of bubbles in fluidized bed by means of meassuring a pressure fluctuation in the fluidized bed. A pressure probe system has used to measure the pressure. The data concerned with bubble rising velocity, bubble size, distribution of bubbles and frequency of bubble generation or decay are obtained to find the flow characteristics of bubbles in the fluidized bed. The result obtained from this experimental study can be used to design the fuel feeding system of fluidized bed combustion type incinerator. And it is possible to predict the mixing of waste material and fluidizing material.
Wind Tunnel Test of Floating Offshore Structure
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 125~137
Experimental wind tunnel tests have been attempted to investigate the aerodynamic characteristics of floating offshore structure using some types of scaled mldels. The static behaviors of lift, drag forces and pitching moment of its models are measured to exammine the relationship between wind loads and incidence angle, wind velocity, shape of models. The effect of solid ground has been obtained also.
An Experimental Study of the Turbulent Swirling Flow and Heat Transfer Downstream of an Abrupt Expansion in a Circulat Pipe with Uniform Heat Flux
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 138~152
Many studies of heat transfer on the swirling flow or unswirled flow in a abrupt pipe expansion are widely carried out. The mechanism is not fully found evidently due to the instabilities of flow in a sudden change of the shape and appearance of turbulent shear layers in a recirculation region and secondary vortex near the corner. The purpose of this study is to obtain data through an experimental study of the swirling flow and heat transfer downstream of an abrupt expansion in a circular pipe with uniform heat flux. Experiments were carried out for the turbulent flow nd heat transfer downstream of an abrupt circular pipe expansion. The uniform heat flux condition was imposed to the downstream of the abrupt expansion by using an electrically heated pipe. Experimental data are presented for local heat transfer rates and local axial velocities in the tube downstream of an abrupt 3:1 & 2:1 expansion. Air was used as the working fluid in the upstream tube, the Reynolds number was varied from 60, 00 to 120, 000 and the swirl number range (based on the swirl chamber geometry, i.e. L/d ratio) in which the experiments were conducted were L/d=0, 8 and 16. Axial velocity increased rapidly at r/R=0.35 in the abrupt concentric expansion turbulent flow through the test tube in unswirled flow. It showed that with increasing axial distance the highest axial velocities move toward the tube wall in the case of the swirling flow abrupt expansion. A uniform wall heat flux boundary condition was employed, which resulted in wall-to-bulk temperatures ranging from 24.deg. C to 71.deg. C. In swirling flow, the wall temperature showed a greater increase at L/d=16 than any other L/d. The bulk temperature showed a minimum value at the pipe inlet, it also exhibited a linear increase with axial distance along the pipe. As swirl intensity increased, the location of peak Nu numbers was observed to shift from 4 to 1 step heights downstream of the expansion. This upstream movement of the maximum Nusselt number was accompanied by an increase in its magnitude from 2.2 to 8.8 times larger than fully developed tube flow values.
Dynamic Positioning Control of Floating Platform using
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 153~161
This paper presents a design method of dynamic positioning control system for floating platform with rotatable and retractable thruster using
control technique. The norm band of uncertainty is captured by multiplicative perturbation between nominal model and reduced order model. A controller robust to the uncertainty is designed applying
synthesis. The control law satisfying robust stabillity and nominal performance condition is determined through the mixed sensitivity approach. The evaluation for the resultant controller obtained by
synthesis is done through simulations of the closed loop system. The results of
synthesis are compared to those of the traditional LQ synthesis method.
Development of a Capacitance-type wave Recorder for Measuring Real-Time Wave Height Based on Microprocessor Technique
Journal of Ocean Engineering and Technology, volume 10, issue 3, 1996, Pages 162~167
This paper deals with an implementation method for the one chip microprocessor(8097)-based capacitance type wave recorder for a measuring real-time wave height. The system was developed to make it possible to real-time remote sensing the wave height by deploying the RS-232/422/485 communication methods. The system test results for the developed system such as linearity, system stability and robustness of the disturbance was also verified through the performance tests of the system. Furthermore, the system was developed after due consideration with connecting the public network such as satellite mobile communication system and LAN, through the deploying VLSI(Very Large Scale Integration) design techniques.