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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
Journal Basic Information
Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 16, Issue 3_6 - Nov 1996
Volume 16, Issue 2_6 - Nov 1996
Volume 16, Issue 1_6 - Nov 1996
Volume 16, Issue 3_5 - Sep 1996
Volume 16, Issue 2_5 - Sep 1996
Volume 16, Issue 1_5 - Sep 1996
Volume 16, Issue 3_4 - Jul 1996
Volume 16, Issue 2_4 - Jul 1996
Volume 16, Issue 1_4 - Jul 1996
Volume 16, Issue 3_3 - May 1996
Volume 16, Issue 2_3 - May 1996
Volume 16, Issue 1_3 - May 1996
Volume 16, Issue 3_2 - Mar 1996
Volume 16, Issue 2_2 - Mar 1996
Volume 16, Issue 1_2 - Mar 1996
Volume 16, Issue 3_1 - Jan 1996
Volume 16, Issue 2_1 - Jan 1996
Volume 16, Issue 1_1 - Jan 1996
Selecting the target year
Laboratory Study of Frictional Flows in Commercial Pipes
Yoo, Dong-Hoon ; Han, Sang-Ho ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 1~1
Colebrook-White formula and Hazen-Williams formula are widely used for estimating the friction factor of commercial pipes. On the other hand Yoo (1993, 1995) has developed mean friction factor method and mean zero velocity point method as new approaches. His approaches were verified using the data collected by Colebrook. Yoo and Won (1995) have found the clear trends of equivalent roughness height and probability related to the pipe diameter. The present study is again focused on the verification of Yoo's approaches by conducting laboratory experiments. Galvanized iron pipes were used for the laboratory experiments, and in order to simulate the flow in commercial pipe several rough joints were artificially made by welding steel plates inside the pipe. The equivalent roughness of nojoint smooth galvanized pipe was estimated to be 0.032 mm, and the probability of smooth wall area was found to be decreased by increasing the number of joints.
Design of Stable Bed Based on the Rational Methods in Small Alluvial Channels
Kim, Dong-Hyeon ; Paik, Joong-Cheol ; Heo, Jun-Haeng ; Cho, Won-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 13~13
This study is to improve the existing stable bed design method using regime theory and to design stable bed in small alluvial channels. The modified rational methods replacing Du Boys formula in Chang's rational method by Engelund-Hansen, Ackers-white, and Yang formulas were introduced and compared with the other methods. Chang's and the modified rational methods proposed in this paper were analyzed and applied to the lower section of 8km of Dalcheon, a tributary of the Namhan River, which was supposed as a stable bed. The computed bed levels for the modified methods were close to the actual bed levels as follows : Engelund-Hansen formula for small channel section, Ackers-White formula for large channel section, Yang's unit stream power equation for gravel bed section. The modified rational methods were better than Chang's method for various sediment size and section geometry.
Flood Frequency Analysis at Indogyo Station in Han River Basins(II) - Estimation of Flood Quantiles -
Kim, Kyung-Duk ; Seo, Kyu-Woo ; Heo, Jun-Haeng ; Cho, Won-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 23~23
Annual maximum flood data at Indogyo in Han River basins were divided into three groups (data I:
, data II:
, data III:
excluding missing data from 1941 to 1951) for flood frequency analysis. The flood quantiles of the selected probability distributions such as Wakeby-5, Wakeby-4, GEV, Gumbel, gamma-3, gamma-2, and Weibull-2 were estimated for each data. Also, flood frequency analyses based on the plotting position formula and the historical flood information were performed. As results, Wakeby-5 model has the largest flood quantiles for data II and Gumbel model for data III among the selected probability distributions for the same return periods. Frequency analysis based on the historical flood information shows that the return periods of the observed maximum flood (32,986 cms) we 122 year (censoring level 22,000 cms and 128 year (censoring level 25,000 cms), respectively.
Numerical Calculation of Hydrodynamic Pressure Acting on a Gravity Dam with Boundary Integral Equation Method
Cho, Yong-Sik ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 33~33
The hydrodynamic pressure acting on gravity dams due to ground motions should be considered in designing a dam. If flow is incompressible and the fluid is inviscid, the hydrodynamic pressure is governed by three-dimensional Laplace equation. A boundary integral equation model based on analytical line integrals is used to compute the hydrodynamic pressure acting on a simplified gravity dam-reservoir system during earthquakes. The obtained numerical solutions are compared with existing two-dimensional experimental data and analytical solutions. The agreement between the present numerical solutions and those experimental data and analytical solutions is excellent. The model is then used to investigate three-dimensional effects of a complex dam-reservoir system. If proper initial and boundary conditions are provided, the developed three-dimensional boundary integral model can be applied to other hydrodynamic problems such as the numerical analyses of groundwater movement and long wave generation, propagation and nth-up process.
Application of the Multigrid Method for Solving 2-D Navier-Stokes Equation
Lee, Jong-Seol ; Choi, Seong-Yeol ; Heo, Jun-Haeng ; Cho, Won-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 43~43
The multigrid method was applied to solve the 2-D Wavier-Stokes equation for circulating flow in a rectangular driven cavity. The vorticity-stream function variable form was used as a governing equation. The upwind and central difference schemes were selected for discretizing the conservative and nonconservative forms of the vorticity transport equation, and then were solved by ADI method. The multigrid method was applied to improve the solution procedures on the aspects of computation time and convergence for the stream function equation. As the number of grid points increases, the performance of the multigrid method is better than that of the existing method. Also, the central difference scheme for the vorticity transport equations was reasonable for the low Reynolds number, while the upwind difference scheme for the high Reynolds number.
Boundary Treatment Techniques of Numerical Model for the Prediction of Harbor Oscillation
Yoon, Sung-Bum ; Lee, Jong-In ; Lee, Jong-Kyu ; Chae, Jang-Won ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 53~53
In this paper a numerical model using finite difference method is presented for the prediction of harbor oscillation. A linear hyperbolic type equation including the effects of energy dissipation and nonlinear dispersion relationship. The efficient radiation of outgoing waves is achieved by employing the sponge layer and internal wave generation techniques. These are tested for 1-dimensional wave generation and propagation. In order to verify the numerical model, it is applied to the refraction-diffraction of waves due to the elliptic shoal on a sloping beach and the wave resonance inside the rectangular harbor which is open to the sea. The numerical results are compared with the experimental data of Berkhoff et al. (1982), Ippen and Goda (1963), and Lee (1969).
Three-Dimensional Numerical Modelling of Tidal Currents in Masan-Jinhae Bay
Jung, Tae-Sung ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 63~63
A three-dimensional numerical model, which is to calculate the vertical eddy viscosity by
turbulence model. was applied to simulate the tidal currents in Masan-Jinhae Bay. The simulated results were compared with a field data set showing good agreement. The used turbulent constants are the same with that of Kori study. This study has shown the possibility that
turbulence model is applicable to various sites without any tuning process of turbulent constants. The vertical distributions of simulated horizontal velocity are nearly logarithmic.
Moving Boundary Condition on a Sloping Beach
Cho, Yong-Sik ; Yoon, Tae-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 73~73
The shoreline, where the water depth becomes zero, moves continuously as waves rise and recede. Therefore, a special boundary condition is required to track properly the movements of the shoreline in numerical modeling of the behavior of tsunamis or tides near the coastal zone. In this study, a moving boundary treatment has been invented to describe the moving shoreline accurately and an oscillatory flow motion in a circular paraboloid basin has been used to validate the performance of the developed moving boundary algorithm. Plots of instantaneous free surface displacements are compared with those of existing analytical solutions. A reasonable agreement is observed. The developed moving boundary technique also works well for the practical problem.
Removal of Trichloroethylene and Phenol by Cometabolism of Microorganism Immobilised in Celite
Shin, Hang-Sik ; Lim, Jae-Lim ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 83~83
Batch tests were performed to investigate the feasibility of cometabolic degradation of TCE by activated sludge from a coking wastewater plant. It was observed that these microorganisms were able to degrade TCE following growth with phenol, but TCE significantly inhibited phenol degradation in a concentration dependent manner. The packed-bed bioreactor filled with Celite bead was operated contiuously during 285 days. Immobilised microorganisms in is reactor degraded effectively TCE utilizing phenol as carbon and energy source. The removal efficiency of TCE in this reactor was over 86.5% of 4mg/l TCE. However, it was observed that high concentration of phenol inhibited TCE degradation in the Celite bioreactor. The isolated cells from this reactor possessed toluene dioxygenase and catechole-2,3-dioxygenase activities that is known to be resposible for the degrading of TCE. It was observed by scanning electron microscopy (SEM) that the bacteria, straight or slightly curved rods type immobilised the surface pores of the Celite bead.
Enhancement of Phosphorous Removal by Supplemental Iron Ions via Corrosion in Intermittently Aerated Activated Sludge Units
Ko, Kwang-Baik ; Kim, Han-Soo ; Yim, Seong-Keun ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 93~93
An effective method was proposed in order to remove influent phosphorous in intermittently aerated activated sludge units into which iron ions were supplied via corrosion from the surface of an iron plate. Acclimated activated sludge in synthetic wastewater were supplied in a series of lab-scale batch reactors which were operated in the 2 hour-anoxic and 2 hour-aerobic mode during a 12 hour period. The
removal efficiency in the reactor with the iron plate was significantly higher than that in the reactor without the iron plate. It indirectly indicates that
in the influent were precipitated in insoluble or low-solubility salts with the oxidized iron ions via corrosion from the iron plate. The removal efficiency of COD and
in the influent were about 95% and about 100%, respectively, at the end of the 12 hour period. In both of the reactors with an iron plate or without it,
concentrations increased in the aerobic condition due to nitrification, and decreased in the anoxic condition due to denitrification. This rising and falling pattern of the
concentrations were repeated during this period. The proposed operational scheme, the 2 hour-anoxic and 2 hour-aerobic mode in aeration basins with iron plates, in this study seems relatively simple and easy to use in enhancing phosphorous removal in the conventional activated sludge wastewater treatment plants.
Anaerobic Phase Separation in Hydrogen Partial Pressure
Min, Kyung-Sok ; Ahn, Young-Ho ;
Journal of The Korean Society of Civil Engineers, volume 16, issue 2_1, 1996, Pages 101~101
Anaerobic phase separation in hydrogen partial pressure was developed to enhance stability of biopellet. And behavior of each reactor and reaction product as well as characteristic of biopellets were investigated as a function of pH condition. From performance of two-in-series UASB(high/low
) system, effective phase separation in hydrogen partial pressure phase was observed. In the first stage UASB reactor operated with high
condition, a lot of soluble organic degradation and pelletization of biopellets with high activity were carried. And in the second stage UASB reactor operated with low
condition, autolysis of biopellets as well as removal of reaction products as SCFAs were observed. Optimum pH conditions for the first and second UASB reactor were 7.0 each. Especially, in high
reactor, it was observed pelletization process with high specific cell yields and extracellular polymer (ECP) excretions due to adequate growth environment.