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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 17, Issue 3_6 - Nov 1997
Volume 17, Issue 2_6 - Nov 1997
Volume 17, Issue 1_6 - Nov 1997
Volume 17, Issue 3_5 - Sep 1997
Volume 17, Issue 2_5 - Sep 1997
Volume 17, Issue 1_5 - Sep 1997
Volume 17, Issue 3_4 - Jul 1997
Volume 17, Issue 2_4 - Jul 1997
Volume 17, Issue 1_4 - Jul 1997
Volume 17, Issue 3_3 - May 1997
Volume 17, Issue 2_3 - May 1997
Volume 17, Issue 1_3 - May 1997
Volume 17, Issue 3_2 - Mar 1997
Volume 17, Issue 2_2 - Mar 1997
Volume 17, Issue 1_2 - Mar 1997
Volume 17, Issue 3_1 - Jan 1997
Volume 17, Issue 2_1 - Jan 1997
Volume 17, Issue 1_1 - Jan 1997
Selecting the target year
Assured River Discharge Forecasts During Drought Periods
Lee, Dong-Ryul ; Yoon, Yong-Nam ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 287~287
The objective of this study is to develop a forecasting model for the assured river discharge which is the flow supplied to river by groundwater aquifers of concerning basin during drought periods. The relationships between discharges of the 10 days before the end point of groundwater recession curves and discharges at the end point for each season are derived to develop the forecasting model. Then. such relationships are used to construct "10 days interval continuous groundwater recession curves" from September to next August. If there is no rain or little groundwater recharge in future these curves can be used to forecast the assured discharge in the river. Minimum assured discharges supplied to river by aquifers of major river basins in Korea are also presented using these curves. The results of this study are very fruitful in the effective use of available water resources and the establishment of long-term water resources management plan during the prolonged drought periods.
Capillary Tension Head Variance in Unsaturated Heterogeneous Stratified Soils
Yun, Soung-Yong ; SonU, Jung-Ho ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 297~297
Capillary tension head variance is evaluated in the case of unsaturated flow in stratified soils using a three-dimensional stochastic model (or a large-scale model) The large difference in the correlation scales in stratified soils simplifies stochastic model allowing for analytical evaluations and derivation process of general equations. Also. derived are simplified asymptotic equations, which are valid at particular ranges (wetting front, wetting condition, drying condition) of the mean flow characteristics. Examples applying the theoretical results to two real soils are presented. It is found that capillary tension head variance show large-scale hysteresis which is due to spatial variability of soil property. Also results show that capillary tension head variance is larger in the case of wetting condition than that in the case of drying condition.
Analysis of the Flood Level Changes by the Vegetation on the Floodplain of Urban River
Cho, Hong-Je ; Lee, Jun-Yong ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 309~309
A close-to-nature river-improvement technique was studied using vegetation on the overbank area of the urban rivers which lack river-friendliness and hydrophilic waterfront. In this study the numerical analysis based on the theory of deadwater zone by vegetation and its effects on hydraulic characteristic changes suggested by Fukuoka was used. The effects of the densely distributed vegetation (bamboos) of the overbank in the Taehwa river of Ulsan city on the increase of flood water level was not so high, and the increase of flood water level by the vegetation of 2.5% of river width was nearly zero. The results showed that river-friendliness and waterfront amenity would be improved by proper vegetation on the overbank of the urban river without any serious effects on flood water level.
Laboratory Investigation on Entrainment of Fluid Mud in Sediment-Stratified Shear Flows
Hwang, Kyu-Nam ; Lee, Jong-Kyu ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 319~319
Laboratory experiments were conceived and carried out to simulate the entrainment process of fluid mud due to turbulent flow-induced shear at the interface of a two-layered water-fluid mud system, which is a natural and common occurrence in water environments with muddy bottoms. Data for the entrainment of fluid muds of different densities and compositions were obtained generating mean shear flows with a specially designed disk pump system in a race track-shaped recirculating flume The entrainment rate of fluid mud was examined as a function of the overall Richardson number and compared with that for the two-layered water-salt water system. It is noted that sediment settling counteracts the otherwise buoyancy dependent entrainment of fluid mud. and that the settling effect leads to a measurably decreased entrainment rate at higher Richard-son numbers in comparison with entrainment of salt water, due to additional dissipation of turbulent kinetic energy in the interfacial layer. The effect of sediment composition on entrainment is also investigated using a kaolinite. a mixture of kaolinite and a bentonite, and a lake sediment as constituents of fluid mud. The effect of cohesion is to possibly reduce the entrainment rate, since increasing cohesion requires increasingly stronger shear force and hence flow energy to break larger than the inter-particle bonds necessary for particulate entrainment.
Experimental Investigation of Mixing of Heated Water Discharged by Submerged Multiport Diffuser
Seo, Il-Won ; Kim, Hong-Sik ; Kim, Dai-Geun ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 335~335
A hydraulic model study has been performed to investigate the behavior of submerged multiport system that can maximize initial dilution of heated water discharged from power plant. When tee diffuser and co-flowing diffuser that have been the typical types of submerged multiport diffuser are used for discharging heated water. temperature field around diffuser and minimum dilution in near field is measured and analyzed in detail Findings obtained in this study are as follows: The analysis of
dimensionless excess temperature area for each diffuser shows that excess temperature area of tee diffuser seldom exists as the value of volume flux ratio is higher than 120 and that of co-flowing diffuser is zero. when volume flux ratio is higher than 20. Minimum dilution of co-flowing diffuser is much higher than that of tee diffuser As volume flux ratio increases, dilution of co-flowing diffuser increases very rapidly. but that of tee diffuser increases rather slowly. Dilution of tee diffuser is not much affected by increase of crossflow velo-city whereas dilution increases as water depth increases. The dilution of co-flowing diffuser increases rapidly as either velocity of crossflow or water depth increases.
Development of Experience Knowledge Based Expert System for Joint Operation of Chungju and Soyanggang Multipurpose Reservoir during Drought
Shim, Soon-Bo ; Lee, Hee-Seung ; Koh, Deuk-Koo ; Kim, Man-Sik ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 347~347
An Experience Knowledge Based Expert System was developed for the joint operation of Chungju and Soyanggang multipurpose reservoirs in the Han river basin during the drought. Expert knowledges for the establishment of the knowledge base were provided by the reservoir operation experts of the Korea Water Resources Corporation. The developing tool for the system was CLIPS software that includes the inference engine and functions to build the user interface module and knowledge base module. The developed system was applied to the drought period in 1994-1995 to derive the joint operation rules during the period. which were tested through simulation. The simulation results showed that the developed system can appraised the acceptable joint operation rules for the Chungju and Soyanggang Multipurpose reservoirs during the drought.
Internal Generation of Waves for Time-Dependent Mild-Slope Equations
Lee, Chang-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 359~359
The technique of generating waves internally is studied for two time-dependent mild-slope equations developed by Copeland (1985) and by Radder and Dingemans (1985) the velocity of disturbances caused by the incident wave is the phase velocity from the viewpoint of mass transport and it is the energy velocity from the viewpoint of energy transport. For Radder and Dingemans' equations. the desired energy of incident wave cannot be obtained from the viewpoint of mass transport from which the desired energy was successfully obtained by Larsen and Dancy (1983) in the Boussinesq equations and by Madsen and Larsen (1987) in Copeland's equations. However for all the two equations developed by Copeland and Radder and Dingemans. the desired energy of incident wave can be obtained from the viewpoint of energy transport. For horizontally two-dimensional case. an efficient technique of internal generation of multi-directional mono-chromatic waves is suggested.
Internal Generation of Multi-Directional Random Waves for Time-Dependent Mild-Slope Equation Model
Lee, Chang-Hoon ; Suh, Kyung-Doug ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 367~367
We studied the technique of internal generation of multi-directional random waves for the time-dependent mild-slope equations developed by Radder and Dingemans (1985) Following Lee's (1997) idea that the velocity of surface disturbances caused by the incident wave is the energy velocity, we generated numerically multi-directional mono-chromatic waves. and also uni-directional and multi-directional random waves. The numerical results showed that both energy and phase of incident waves are properly produced for all the cases.
Tidal Computation and Energy Dissipation for the
Tide in the Global Ocean
Suh, Kyung-Suk ; Choi, Byung-Ho ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 377~377
Two-dimensional numerical models with the resolution of
have been established to investigate the
distribution of global ocean tides. Especially a
numerical model has been applied to the computation of detailed tidal distributions and tidal energy dissipation in the marginal seas and the shelf seas. The
tidal charts obtained by the
model have been compared with the the existing ones by global nomerical models, by the altimetry-derived. Also, the computed harmonic constants have been compared with the pelagic observations. The results obtained by
model show better agreement with the existing global charts and the observations than those obtained by
model. The tidal energy supplied from the Moon and Sun is mostly dissipated by the bottom friction in shallow seas. In this study, the rates of energy dissipation due to the bottom friction calculated by
model, respectively are the
W The computed frictional dissipation is compared with that obtained by the existing numerical models and with the altimetry-derived value. The dissipation rate by
model agrees much better with the results of altimetry-derived than those by
model. Tidal distribution which could be hardly reproduced with the existing global chart due to the low resolution in the shelf seas and the marginal seas, has been presented by
model. The possibility has been presented that the tidal numerical model with
resolution can evaluate the tidal distributions in the global ocean and the shelf seas simultaneously.
A Study on the Optimal Operation of the Intermittently Aerated Fluidized Bed
Lee, Jeoung-Su ; Kim, Jong-Guk ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 395~395
The effect of nonaeration/aeration ratio and cycle on the intermittently aerated fluidized bed were studied experimentally. and the obtained results were as follows : 1. Under the intermittent aeration. BOD removal rate was from 98.3% to 88.6% in the range of non-aeration rate 0.4 to 0.75. and the most economic non-aeration rate was 0.5. 2. Under the non-aeration rate of 0.5, effluent BOD improved from 4.2 mg/l to 2.5 mg/l as a non-aeration/aeration period was reduced. Effluent SS was getting better from 4.2 mg/l to 2.5 mg/l, too. 3. The repeating stress such as interception of air supply seems to promote the activity of a microorganism. 4.
ratio (0.56) of the intermittent aeration was alike with 0.55 of continuous aeration, and oxygen consumption rate (
) of a microorganism in intermittent aeration was lower than 0.55 of continuous aeration. 5. Even though a non-aeration/aeration period was reduced to 10/20 min. the prosperity of filamentous bacteria was restrained nicely.
Effect of Nitrate on the Performance of the Upflow Anaerobic Sludge Blanket Process
Kim, Hee-Jun ; Chung, Tai-Hak ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_4, 1997, Pages 403~403
Nitrate was introduced to the bench scale UASB reactor treating concentrated starch waste, and the reactor performance was investigated. Nitrate reduction took place at the beginning of nitrate introduction, and the sludge granules carrying out anaerobic digestion already posessed sufficient capacity of nitrate reduction. Complete denitrification was achieved up to nitrate nitrogen concentration of 500 mg/L. However, the nitrate removal efficiency decreased below 90 percent because of insufficient organic matter when the nitrate nitrogen reached 800 mg/L. Gas production decreased as the influent nitrate concentration increased because of less gas production in nitrate reduction comparing with methane fermentation. The nitrate reducing bacteria were superior to the methane producing bacteria in the competition of organic substrate. and the organic matter was preferably used as an electron donor in the denitrification. Based on the reaction stoichiometry it was found that the acetic acid rather than glucose was main substrates of the denitrification reaction. As the nitrate addition was stopped. fast recovery of the methane fermentation took place due to nonexistence of the substrate competition.