• Title/Summary/Keyword: Oil fence

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Characteristics of Flow Field at Curved Section of Oil Fence using PIV Measurements and CFD Simulations (PIV 계측과 CFD 해석을 통한 오일펜스 만곡부 단면에서의 유동장 특성)

  • Kim, Tae-Ho;Jang, Duck-Jong;Na, Sun-Chol;Bae, Jae-Hyun;Kim, Dae-An
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.17 no.1
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    • pp.29-37
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    • 2011
  • PIV measurements of the velocity field, pressure field, vorticity, and turbulent intensity in the rear of curved section of an oil fence with current speed showed that the flow directions in the rear of flow boundary area were similar to those in the front of it. As the current speed increased, the patterns of pressure distribution were changed, and the turbulent flow became more irregular. CFD simulations under the same conditions as the PIV tests showed that the flow patterns of the wake were similar to those by PIV tests in speed of 0.3 m/s and less, but were distinctively deviated from those in 0.4 m/s due to the flexibility of the oil fence, which was not properly taken care of in CFD modeling.

On Oil-Water Interface of Oil Layer Contained in Tandem Oil Fences (이중유벽 사이에 가두어진 기름층의 거동특성)

  • Doh D.H.;Hyun B.S.;Choi S.H.;Hong S.H.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.3 no.1
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    • pp.25-34
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    • 2000
  • A panoramic-PIV technique is employed to characterize the travelling tip vortices and the profile of oil-water Interface in the tandem fence arrangement. Instantaneous as well as time-averaged velocity profiles of the water layer close to the interface were obtained to evaluate the possibility of measuring the shear stress distribution on oil-water interface. It was proven that the present technique could provide some qualify data precise enough to resolve detailed flow structures inside a shear layer formed on oil-water interface provided it is nearly stationary.

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Study on Prediction for Prompt Countermeasures to Oil Spread in Ocean (해안기름유출사고에 의한 기름확산 예측 방법 연구)

  • Kim, Young-Bok
    • Journal of Ocean Engineering and Technology
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    • v.25 no.2
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    • pp.108-112
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    • 2011
  • When oil spills occur in the ocean because of a ship collision or grounding, the oil in the sea will spread to the coastline. To effectively and promptly prevent such an oil spread, the prediction of the direction and speed of the spreading oil must be made. By applying the coastal wave diffusion theory with a consideration of the effects of wind and current, the oil spreading direction and speed can be predicted promptly so that the National Disaster Prevention System can effectively and promptly take countermeasures against the attack and contamination of the coastline by such oil bands.

Behavior of Oil-Water Interface between Tandem Fences (이중 유벽 사이의 기름과 물의 계면의 거동)

  • Kang Kwan Hyoung;Lee Choung Mook
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.2 no.2
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    • pp.70-77
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    • 1999
  • The disturbance of oil-water interface confined between tandem fences caused by a sequence of traveling vortices below the interface is investigated. The traveling vortices are assumed to be those detached from the tip of the fore fence. The potential flow is assumed and the density interface is replaced as a sheet of vortex. The shape of the interface is predicted by tracing a finite number of marker particles placed at the interface. The velocity of the marker particles is determined by the Biot-Savart integral along the vortex sheet plus the contribution from the traveling point vortices. The rate of change of vortex-sheet strength is predicted by using an evolution equation for vorticity. The calculated results obtained for various conditions demonstrate that the large amplitude of interfacial wave following the moving vortek can be generated by the vortices.

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Containment Failures of Oil Restricted by Vertical Plates in Current (유벽에 갇힌 기름층의 조류중 손실에 관한 연구)

  • Song Museok;Hyun Beom-Soo;Suh Jung-Chun
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.1 no.2
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    • pp.40-51
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    • 1998
  • The interaction of contained oil slicks with current was investigated with a two-dimensional experimental setup in the circulating water channel facility. A vertical plate was used to contain the oils against the currents and the evolution of the oil slick, mainly focusing on the water/oil interface, was examined with an aid of a laser sheet. Two different oils - soy bean oil and diesel oil - were studied with varying the current speed (10 cm/sec to 35 cm/sec), the barrier depth (4 cm and 8 cm) and the volume of oil (2 liter to 12 liter). Different types of the interface behavior were observed according to the conditions and their mechanism was discussed based basically on the dimensional analysis. The critical speeds of two types of oil loss mechanism (entrainment failure and drainage failure) were also examined.

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A Study on Optimization of The Concentration of Cutting Oil to be used for Cutting (절삭가공(切削加工)에 사용(使用)되는 절삭유(切削油)의 농도최적화(濃度最適化)에 관(關)한 연구(硏究))

  • Kim, Gue-Tae;Kim, Won-Il
    • Journal of the Korean Society of Industry Convergence
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    • v.16 no.3
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    • pp.95-102
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    • 2013
  • It is indispensable to modern society metal processing since the industrialized rapidly, but it is a metalworking cutting fluid immediately. In addition, this means selecting a emulsion on the basis of quality criteria processing method, the material of the material, cutting depth, cutting speed, Djourou fence Liang, and surface roughness, cutting oil, the shape of the device based on the emulsion, I will be the structure of the tank, filtration equipment also changes. In particular, acting bacteria is now breeding in response to the passage of time due to metal ion degradation due to heat generated hydraulic fluid leakage, humidity tung, during processing, seep from processing material at the time of processing the water-soluble cutting oil for generating the malodor by dropping significantly the performance of the cutting oil to corruption from, sometimes by introducing various additives to suppress spoilage in advance. In this study, we expect the effect of the cost reduction in the extension of fluid replacement cycle through the application of the management apparatus and deep understanding in the management of cutting fluid, the working environment through the understanding and interest of workers in the production site more than anything I try to become useful for the improvement.

Morphological Changes of the Beach and Foredune by Sand Fences - A Case of Shindu Coastal Dune Area - (사구울타리 설치 후 해빈과 전사구의 지형 변화 - 신두리 해안사구를 사례로 -)

  • SEO, Jong Cheol
    • Journal of The Geomorphological Association of Korea
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    • v.17 no.1
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    • pp.85-93
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    • 2010
  • After the notorious Taean Oil spill in Dec. 2007, a series of sand fences made of fishing net were installed in front of foredune in Shindu dune area. This paper aims to understand the temporal and spatial characteristics of morphological changes of the beach and foredune. About 1m high sand accumulated around sand fences for the last 2 years. While a lot of sand deposited during the winter season (from autumn to spring), small amount of sand eroded and deposited during summer season (from spring to autumn) without big morphological changes. These results mean that sand fences help nature deposit sand near beach and foredune area.

Control of Cyanobacteria and Phytoplankton Using Physico-chemical Methods (물리·화학적 방법을 이용한 Cyanobacteria와 식물 플랑크톤의 제어)

  • Jheong, Weon-Hwa;Jeon, Eun-Hyung;Ahn, Tea-Young
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.5
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    • pp.75-84
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    • 2004
  • Loess, PAC, MACF and plants were applied to the control of the phytoplankton bloom in laboratory and in field, In field experiment using oil fence, 5ppm concentration of coagulant(PAC) was observed to be effective in controlling the cyanobacterial bloom, resulting in 90% removal of cyanobacteria and phytoplankton from the water column, hi case of Synedra sp., however, only 50% of biomass decreased with the same PAC concentration. MACF(micro-air bubble coagulation and floating), a kind of physicochemical method, was applied to the column of the Kyongan stream and resulted in over 80% chlorophyll a and 73.5% TP removal, Chlorophyll a and total phosphorus were effectively removed from water body when 2.0 g/L of loess with the particle radius of 125 ${\mu}m$ was inputted. In case of experiments involving plants, big cone pine, gingko, and pine needle were observed to be effective in restraining phytoplankton bloom at 0.5g/200ml level. During a field test done at Kyungan stream, where Microcystis heavily occurred, Pine needle and big cone pine were observed to be effective on suppressing algal growth.

An Experimental Study on the Fire Risk at Welding·Cutting Process (용접·절단 작업시 화재위험성에 관한 실험적 연구)

  • Lee, Sung-Ryong
    • Fire Science and Engineering
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    • v.26 no.3
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    • pp.60-66
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    • 2012
  • In this study, it was evaluated the fire risk during welding cutting tasks. Welding-cutting machines are representatively used at construction sites. Inverter AC/DC TIG welding macnine and inverter air plasma cutting machine were used in experiments. Temperature of spreaded cinders was measured using a thermal camera. Cinder sizes and spread range were measured according to the height and input current. It was also evaluated the fire risk during welding-cutting process, when flammable materials were located around the working area. There were used hay, dust fence, urethane foam, vinyl, paper and oil as flammable materials. Temperature of spreaded cinders was reached at about $450^{\circ}C$. Cinders were spread approximately 4.7 m, when a worker carried out cutting process at 2.5 m height. The possibility of a fire is very high, when flammable materials were located around the working area.

A Study on the Growth Diagnosis and Management Prescription for Population of Retusa Fringe Trees in Pyeongji-ri, Jinan(Natural Monument No. 214) (진안 평지리 이팝나무군(천연기념물 제214호)의 생육진단 및 관리방안)

  • Rho, Jae-Hyun;Oh, Hyun-Kyung;Han, Sang-Yub;Choi, Yung-Hyun;Son, Hee-Kyung
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.3
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    • pp.115-127
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    • 2018
  • This study was attempted to find out the value of cultural assets through the clear diagnosis and prescription of the dead and weakness factors of the Population of Retusa Fringe Trees in Pyeongji-ri, Jinan(Natural Monument No. 214), The results are as follows. First, Since the designation of 13 natural monuments in 1968, since 1973, many years have passed since then. In particular, despite the removal of some of the buried soil during the maintenance process, such as retreating from the fence of the primary school after 2010, Second, The first and third surviving tree of the designated trees also have many branches that are dead, the leaves are dull, and the amount of leaves is small. vitality of tree is 'extremely bad', and the first branch has already been faded by a large number of branches, and the amount of leaves is considerably low this year, so that only two flowers are bloomed. The second is also in a 'bad'state, with small leaves, low leaf density, and deformed water. The largest number 1 in the world is added to the concern that the s coverd oil is assumed to be paddy soils. Third, It is found that the composition ratio of silt is high because it is known as '[silty loam(SiL)]'. In addition, the pH of the northern soil at pH 1 was 6.6, which was significantly different from that of the other soil. In addition, the organic matter content was higher than the appropriate range, which is considered to reflect the result of continuous application for protection management. Fourth, It is considered that the root cause of failure and growth of Jinan pyeongji-ri Population of Retusa Fringe Trees group is chronic syndrome of serious menstrual deterioration due to covered soil. This can also be attributed to the newly planted succession and to some of the deaths. Fifthly, It is urgent to gradually remove the subsoil part, which is estimated to be the cause of the initial damage. Above all, it is almost impossible to remove the coverd soil after grasping the details of the soil, such as clayey soil, which is buried in the rootstock. After removal of the coverd soil, a pestle is installed to improve the respiration of the roots and the ground with Masato. And the dead 4th dead wood and the 5th and 6th dead wood are the best, and the lower layer vegetation is mown. The viable neck should be removed from the upper surface, and the bark defect should undergo surgery and induce the development of blindness by vestibule below the growth point. Sixth, The underground roots should be identified to prepare a method to improve the decompression of the root and the respiration of the soil. It is induced by the shortening of rotten roots by tracing the first half of the rootstock to induce the generation of new roots. Seventh, We try mulching to suppress weed occurrence, trampling pressure, and soil moisturizing effect. In addition, consideration should be given to the fertilization of the foliar fertilizer, the injection of the nutrients, and the soil management of the inorganic fertilizer for the continuous nutrition supply. Future monitoring and forecasting plans should be developed to check for changes continuously.