• Title/Summary/Keyword: Green Water

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The Optimum Design of Green Water Protector for FPSO (FPSO - Green Water Protector 구조 최적 설계)

  • Bae, Myung-Hyun;Kim, Sung-Jun;Moon, Jung-Yang
    • Special Issue of the Society of Naval Architects of Korea
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    • 2007.09a
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    • pp.94-98
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    • 2007
  • The latest development of the submarine oil field and the deep-sea explorer, FPSO is commonly proposed and used for offshore oil production. And because the fundamental requirement of FPSOs to remain moored at their position, they are unable to avoid severe weather and environment. FPSO normally operates head to the weather, and sensitive equipment located the exposed area will be influenced by green water damages, the damages may occur to both onboard equipment and topside structures with resulting risk to personnel. In this paper, the main focus considers the physical structures of green water protector in order to preserve topside structures, equipment and personnel from green water.

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Investigation of Wave Resistance Performance for Ships and Offshore Structures based on Arbitrary Lagrangian Eulerian Method (ALE 기법을 기반 선박 및 해양 구조물의 내파 성능 분석)

  • Lee, Chi-Seung;Kim, Joo-Hyun;Kim, Myung-Hyun;Lee, Jae-Myung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.553-556
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    • 2011
  • The primary aim of the present study is to propose new design formulae that can be used to evaluate the structural performance of breakwaters installed on container carriers under green water impact loads. A series of numerical analyses for green water impact loads inducing breakwater collapse have been carried out. The well-known fluid-structure interaction analysis technique has been adopted realistically to consider the phenomenon of green water impact loads. The structural behavior of these breakwaters under green water impact loads has also been carried out simultaneously throughout the transient analysis. A verification study of the numerical results was performed using the actual collapse incidents of breakwaters on container carriers. It would be expected that the proposed design formulae, based on the obtained insights, could be used as practical guidelines for the design of breakwaters on container carriers.

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STUDY ON GREEN WATER BEHAVIOR ON RECTANGULAR SHAPED STRUCTURE (사각형 단면 구조물에 대한 그린워터의 생성 특성 연구)

  • Lee, K.N.;Jung, K.H.;Chae, Y.J.;Park, I.R.;Suh, S.B.
    • Journal of computational fluids engineering
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    • v.20 no.2
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    • pp.96-102
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    • 2015
  • In this study, the green water phenomena on rectangular shaped structure is numerically simulated by STAR-CCM+ to investigate the flow pattern including the velocity profiles in bubbly water flow. 5 phases of the formation of green water in front of and over the rectangular shaped structure is simulated at the design condition which is scaled down by 1:125 from FPSO operating in GOM. All numerical results are compared with the experimental results performed in a two dimensional wave flume. The water deformation due to the green water are obtained by the high speed CCD camera with employing the shadow graphy technique, which is allowed to take the bubbly water flow into images. A series of image taken by shadow graphy technique is analyzed with MQD method to calculate the velocity in bubbly water flow.

The Effect of Corrosion Inhibitor on Corrosion Control of Copper Pipe and Green Water Problem

  • Lee, Ji-Eun;Lee, Hyun-Dong;Kim, Gi-Eun
    • Environmental Engineering Research
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    • v.17 no.1
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    • pp.17-25
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    • 2012
  • Concern about green water problem has surfaced as a serious issue in Korea. In order to solve this problem, it is necessary to research inhibition of green water and corrosion control of copper pipe in water service. This paper discovered that moderate corrosion inhibitors can solve the green water problem and copper corrosion in water service by adding the optimal concentration of corrosion inhibitors based on regulation. Firstly, in the case of phosphate based corrosion inhibitors, as dosage of the corrosion inhibitor increases from 1 mg/L to 5 mg/L, the relative effect of corrosion inhibitor declines rapidly. Secondly, except for 1 mg/L dosage of silicate based inhibitor, relative effects of the inhibitor displays a positive number depending on inhibitor concentration. The most significant result is that the amount of copper release shows a downward trend, whereas the phosphate based inhibitor accelerates copper ion release as the inhibitor dosage increases. Thirdly, as the dosage of mixed inhibitors increases to 10 mg/L, the copper release change shows a similar trend of phosphate based inhibitor. Lastly, according to the Langelier saturation index (LI), silicate based inhibitors have the most non corrosive value. Larson ratio (LR) indicates that phosphate based inhibitors are the least corrosive. Korea water index (KWI) represents that silicate based inhibitors are most effective in controlling copper pipe corrosion.

Numerical Computations of Impact Forces Acting on Breakwater Plate of Bow Deck of Container Carrier (전산유체역학을 이용한 컨테이너 선수갑판 쇄파판에 작용하는 충격하중 계산)

  • Lee, Seohyun;Lew, Jaemoon
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.3
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    • pp.198-205
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    • 2015
  • In this study, numerical studies using a Computational Fluid Dynamics(CFD) method were carried out to estimate the green water load acting on the breakwater plate of bow deck of container carrier, KCS. For the green load water load analysis, a full load condition was considered. The relative motions at bow deck were calculated from the seakeepig analysis. Statistical analysis were carried out to estimate the long term response of the relative motions with the North Atlantic wave scatter diagram. The equivalent design wave was determined from the RAO of the relative motions at bow and the long term responses. CFD geometry modeling with three different locations and simulations for the green water loads were carried out in the equivalent design waves. A commercial CFD program, STAR-CCM+ Ver. 8.04, was used and the green water pressures on the breakwater plate were calculated successfully. The CFD analysis for green water loads can be used as a useful design tool for the evaluation of the breakwater plate of the container vessel.

Investigation of structural responses of breakwaters for green water based on fluid-structure interaction analysis

  • Lee, Chi-Seung;Heo, Haeng-Sung;Kim, Young-Nam;Kim, Myung-Hyun;Kim, Sang-Hyun;Lee, Jae-Myung
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.4 no.2
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    • pp.83-95
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    • 2012
  • In the present study, the structural response of breakwaters installed on container carriers against green water impact loads was numerically investigated on the basis of the fluid-structure interaction analysis. A series of numerical studies is carried out to induce breakwater collapse under such conditions, whereby a widely accepted fluid-structure interaction analysis technique is adopted to realistically consider the phenomenon of green water impact loads. In addition, the structural behaviour of these breakwaters under green water impact loads is investigated simultaneously throughout the transient analysis. A verification study of the numerical results is performed using data from actual collapse incidents of breakwaters on container carriers. On the basis of the results of a series of numerical analyses, the pressure distribution of green water was accurately predicted with respect to wave mass and velocity. It is expected that the proposed analytical methodology and predicted pressure distribution could be used as a practical guideline for the design of breakwaters on container carriers.

Current Status and Issues of Green Roof Technology in Korea (한국옥상녹화기술의 현황과 과제)

  • Yang, Byoung-E
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.4
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    • pp.1-7
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    • 2004
  • The purpose of the study is to review current status of green roof technology and to suggest the issues and solutions related with the technological problems of green roof in Korea. The scope of the study is limited to the extensive green roof which requires low maintenance. Technological issues related with green roof include soil, water proofing, water drain, vegetation and maintenance. Several solutions to invigorate green roof technology were suggested as follows; 1)implementation of technical standard for green roof and technology certification system, 2) development of suitable raw materials for green roof, 3) construction guidelines and uniform construction specification, 4) formulation of city ordinance for green roof, and 5) exchange program with foreign green roof organizations.

Effects of Dried Leaf Powders, Water and Ethanol Extracts of Persimmon and Green Tea Leaves on Lipid Metabolism and Antioxidative Capacity in 12-Month-Old Rats (감잎, 녹차의 건분 및 물, 에탄올추출물이 노령쥐의 지방대사와 항산화능에 미치는 영향)

  • 오현명;김미경
    • Journal of Nutrition and Health
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    • v.34 no.3
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    • pp.285-298
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    • 2001
  • The effects of dried leaf powders and water and ethanol extracts of persimmon and green tea on lipid metabolism, lipid peroxidation and antioxidative enzyme activity were investigated in 12-month-old rats. Forty-nine male Sprague-Dawley rats weighing 520$\pm$19g were blocked into seven groups according to body weight. Rats were raised for four weeks with control(no tea leaf powder or extracts) and experimental diets containing either 5%(w/w) dried leaf powders of persimmon(Diospyros kaki Thunb) or green tea(Camellia sinensis O. Ktze), or water or ethanol extract from equal amounts of each dried tea powder. Food intakes of all tea diet groups were higher than that of control. Weight gains and food efficiency ratios of all tea diet groups were not significantly different from those of control. All tea diets decreased plasma triglyceride level, especially, green tea powder and persimmon ethanol diets were more effective than other diet. All the tea diet groups showed decrease in liver triglyceride level, and persimmon powder and ethanol extract increased fecal triglyceride excretion. Plasma cholesterol levels of all the tea diet groups were not significantly different from the control, but control. Fecal cholesterliver cholesterol concegroups were significantlntrations of all tea y lower than that of ol excretions of persimmon powder, green tea ethanol extract, persommon ethanol extract and green tea ethanol extract groups were significantly higher than that of control. Plasma and liver thiobarbituric acid reactive substance(TBARS) concentrations of all the tea diet groups were lower than that of control. Especially, plasma TBARS concentrations of green tea powder and persimmon ethanol extract groups were sinificantly low. Red blood cell(RBC) superoxide dismutase(SOD) activities of persimmon ethanol extract and green tea water extract groups were increased, and RBC catalase activities of all experimental groups were not significantly different. RBC glutathione peroxidase(GSH-px) activities of persimmon ethanol extract, persimmon water extract and green tea powder groups were increased. Liver SOD activities of all the tea diet groups except green tea ethanol extract group were higher than that of control. Liver catalase activities of all experimental groups were not significantly different, and liver GSH-px activity of green tea powder group was significantly higher than that of control. In conclusion, dried leaf powders, and water and ethanol extracts of persimmon and green tea were effective in lowering lipid level, inhibiting lipid peroxidation and increasing antioxdative enzyme activities in 12-month-old rat. Green tea leaf powder with high contents of flavonoids and water soluble dietar fiber was most effective in lowering plasma triglyceride, cholesterol and TBARS level. (Korean J Nutrition 34(3) : 285~298, 2001)

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Physical·Mechanical and Temperature Properties of Fiber Reinforced Porous Green Roof Hwang-toh Concrete (섬유보강 다공성 옥상녹화 황토콘크리트의 물리·역학적 및 온도변화 특성 평가)

  • Oh, Ri On;Kim, Chun Soo;Kim, Hwang Hee;Jeon, Ji Hong;Kwon, Wan Sig;Park, Chan Gi
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.4
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    • pp.65-72
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    • 2013
  • The physical, mechanical, water purification and temperature properties of fiber reinforced porous hwang-toh green roof concrete have been evaluated in this study. The effect of the depending on replacement ratio of blast furnace slag to cement was investigated such that the replacement ratio is varied to 0 % and 30 %. Also, the replacement ratios of hwang-toh were 0, 20 and 30 %. The polyvinyl alcohol fiber was used for the reinforcing fiber. A series of pH test, unit weight, void ratio, compressive strength, after purification and variation of temperature test have been performed to evaluate the performance, water purification effect and temperature properties of the fiber reinforced porous hwang-toh green roof concrete. The test results indicate that the physical and mechanical properties of fiber reinforced porous hwang-toh green roof concrete is affected by the replacement ratio of the blast furnace slag and hwang-toh contents. Results of purifying water showed that the water purification effect of porous hwang-toh green roof concrete is about 40 %. Also, the temperature properties test results indicate the green roof blocks using fiber reinforced porous hwang-toh green roof concrete have insulation and temperature reduction effect.

Underwater Imaging with a blue-green laser (청록색 레이저를 이용한 수중영상 연구)

  • Lee, S.H.;Kim, G.B.;Lee, K.S.;Kim, D.W.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.2180-2182
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    • 2000
  • Laser emission, a part of electromagnetic wave, has short propagation length in water, and the underwater applications of laser are limited. The acquisition of underwater imaging is possible only by using a blue-green laser since the blue-green range has relatively small absorption coefficient in water. We introduce the conditions of the laser required for underwater imaging and the attenuation characteristics of a blue-green laser used in water.

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