• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.389-389
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• 2019

평화의댐은 발전 기능이나 수문 조작 등 인위적인 기능이 전혀 없기 때문에 단순히 홍수조절용댐으로 분류된다. 평화의댐의 여수로는 일반적인 댐과는 달리 임남댐에 대응하기 위한 단계별 건설계획을 고려하여 댐 우안부에 배수터널 형식으로 건설되었다. 현재 평화의댐은 4련의 배수터널(직경 10 m)을 통해서 상류의 유입량을 하류로 방류하고 있다. 방류 능력을 초과하는 홍수가 발생하는 경우에는 일시적인 저류를 통한 제한적인 홍수조절을 수행하고 있지만, 그 효과는 크지 않다. 향후 남북한 관계 개선으로 임남댐의 안정성을 확보할 수 있다면, 평화의댐을 보통의 다목적댐과 같이 활용할 수 있을 것이다. 이에 본 연구에서는 평화의댐을 일반 다목적댐처럼 활용할 수 있는 상황을 가정하고, 일련의 운영방식을 적용하여 운영 방식 변경 전후의 댐의 홍수저류효과를 살펴보았다. 이를 위해 댐의 설계빈도인 200년 빈도의 강우에 대해 모의하고, 여러 가지 시나리오별 저류량-방류량 관계를 구축하였다. 최종적으로 비선형 저수지 모형에 적용하여 댐 저류효과를 정량화하고, 현재 및 잠재 홍수저류효과에 대해 비교하고 토의하였다.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.449-452
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• 2008

Originally developed in Scandinavia over 40 years ago, syphonic roof drainage systems have been in use in the UK since the early 1990's. Since then, many large projects have used the syphonic system to overcome installation problems which would have been difficult to solve using a traditional gravity rainwater system.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.1
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• pp.1843-1853
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• 1970

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.3
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• pp.1997-2002
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• 1970

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.2
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• pp.1923-1926
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• 1970

• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1171-1180
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• 2018

Korea's water transmission system is operated by the nonpressure flow method that flows from highlands to lowlands due to the nature of Korea with many mountainous areas. In order to store water in the highlands, the water pumps are installed and operated. However, In this process, a lot of electrical energy is consumed. therefore, it is necessary to minimize the energy consumption by optimizing the size and operation schedule of the water pumps. The optimal capacity and operation method of the water pump are affected by the size of the tank (distributing reservoir). Therefore, in order to economically design and operate the water transmission system, it is reasonable to consider both the construction cost of the water pump and the tank and the long-term operation cost of the water pump at the step of determining the scale of the initial facilities. In this study, the optimum design model was developed that can optimize both the optimal size of the water pump and the tank and the operation scheduling of the water pump by using the genetic algorithm (GA). The developed model was verified by applying it to the water transmission systems operated in Korea. It is expected that this study will help to estimate the optimal size of the water pump and the tank in the initial design of the water transmission system.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.6
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• pp.67-79
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• 1997

The perpose of this study was to suggest the experimental characteristic of the Cherepnov Water Lifter following the drain mode. The Cherepnov Water Lifter(CWL), which is powered by the potential energy of water, can be set to operate automatically when the water m a tank is drained. In this study, a CWL is constructed in the valve drain controlling mode(VCM) and the siphon drain controlling mode(SCM), and a pressure transducer is installed. It was found that, in the VCM, intake flow volume is proportional to both delivery flow volume and drain flow volume. In the SCM, intake flow volume is proportional to drain flow volume, and the average delivery rate is proportional to both efficiency and the water utilization ratio. Also, in the VCM, the water utilization ratio is 35~49%, efficiency is 62~9O%, average delivery rate is 12.8~81.2$cm^3$/s, and the average drain rate is 14.O~91.5c$cm^3$/s. On the contrary in the SCM, the water utilization ratio is 1.7~38%, efficiency is 3~58%, average delivery rate is 3.1 ~69.2$cm^3$/s, and the average drain rate is shown as 114.5~ 183$cm^3$/s. As a result of the water utilization ratio, efficiency, average delivery rate, and average drain rate are compared, the VCM is found to be superior and the more economical mode. However, the VCM requires manpower and electricity to operate the electronic machinery involved, while the SCM requires no manpower or electricity at all. An economic evaluation of these differences will be necessary in the future. Also, in the SCM, studies to improve water utilization ratio and efficiency, to find the optimum height of the siphon for decreasing the average drain rate, and to determine the radius of curvature of throat have to be conducted in advance, since a large flow rate is drained during the priming action of the siphon.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.240-245
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• 2010

The objective of this study was to determine the effect of different height of drainpipe and growing media soilless cultivated cut rose in container culture. Two experiment were to examine the effect of the drainpipe height and media composition on yield and quality of cut rose, Four different drainpipe height (0, 3, 6, 9 cm) were treated to determine of optimal container type. Yield was the highest at 3 cm drainpipe height, but quality was not significantly affected by drainpipe height. Survival rate of rose was 100%, 100%, 92%, and 92%, respectively. Two different drainpipe height (0, 3 cm) and 7 media composition (pure coir and pelite, and mixed with two media 3 : 1, 2 : 1, 1 : 1, 1 : 2, 1 : 3 v/v) was treated to determine of media composition related to drainpipe height. The supply of nutrient solution was controlled by the signal of water potential at -5 kPa using frequency domain reflectometry (FDR) sensor in mixed coir with pelite 3 : 1, 1 : 1, 1 : 3 (v/v), respectively. Irrigation frequency reduced in high ratio of coir media and 3 cm height of drainpipe. Quality of cut rose except for flower weight and yield until 2nd harvest was not significantly affected by drainpipe height, but yield after 3rd was higher at 3 cm than 0 cm height of darinpipe. In the media composition, yield and qulity of cut rose was increased at high ratio of coir media.

• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.13-17
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• 2012

Recently, our ocean development paradigm is changing so that the development focus has been moved from the port facility developments to creating useful marine space. This paradigm accords well with the current green technology and helps the growth of service industries and the development from this paradigm can become a national land mark. Accordingly, the concept of creating marine waste landfill by the development of resource recycling technology has been introduced for eco-friendly space as an artificial island in future. Therefore, this study introduces the reactive vertical drainage method that is to pursue the purification of pollutants as well as stabilization of newly deposited soils in marine environments. To install the reactive vertical drainage piles for more effective feasibility and constructability, placements of drainage mid-layer are considered in the geotechnical viewpoint. Consolidation characteristics were evaluated by standard consolidation tests after several types of model test. As s result, the application of mid-layer drainage is strongly recommended in the reactive vertical drainage to quickly stabilize newly deposited soils. And vacuum consolidation method has better consolidation characteristic than vertical loading method in terms of the settlements predicted by additional stress for further use as an artificial island.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.269-276
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• 2012

An air core is generated during draining through an axisymmetrically placed circular orifice after rotating a cylindrical tank filled with a liquid. If an air core is generated, the draining flow rate decreases and the draining time increases. In this study, the process of the formation of the air core and internal flow characteristics in a cylindrical tank are studied by numerical methods. Several methods are used in the analysis, and the results are compared with experimental results to obtain the appropriate scheme. Axial, radial, and swirl velocity profiles on a variety of heights are shown graphically, and the internal flow structure is analyzed from the velocity profiles, the vector plot, and the stream function distribution.