• 한국해양공학회지
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• 제32권4호
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• pp.222-227
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• 2018

Most underwater acoustic arrays for low frequency operation are deployed vertically, but a mid-range frequency horizontal array system is being developed by the Korea Research Institute of Ships and Ocean Engineering (KRISO). The horizontal array platform is deployed underwater and kept in place by weather vaning mooring. This is essential because it is nearly impossible to keep a submerged body at a given position in the water without any external force. Hence, the horizontal array platform can maintain the desired position in the presence of a weak tidal current. The objective of this study is to design an underwater platform that can maintain its horizontal position in a weak current. First, the authors investigated various virtual models, selected one of the models, and performed a small model test of the selected model at a basin. We calculated the external forces associated with the 2D motion, and then we conducted a large basin test followed by a circulation water channel test for the manufactured array platform. The results of the simplified 2D motion calculation essentially matched the results of the underwater test.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.419-424
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• 2002

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality In February, 1995. Many experiments should be safely performed to activate the utilization of the HANARO. A flow simulation facility is being developed for the endurance test of reactivity control units for extended life times and the verification of structural integrity of those experimental facilities prior to loading in the HANARO. This test facility is composed of three major parts; a half-core structure assembly, flow circulation system and support system. The flow circulation system is composed of a circulation pump, a core flow pipe, a core bypass flow pipe and instruments. The system is to be filled with de-mineralized water and the flow should be met the design flow to simulate similar flow characteristics in the core channel of the half-core test facility to the HANARO. This paper, therefore, describes an analytical analysis to study the flow behavior of the system. The computational flow analysis has been performed for the verification of system pressure variation through the three-dimensional analysis program with standard k-$\epsilon$ turbulence model and for the verification of the structural piping integrity through the finite element method. The results of the analysis are satisfied the design requirements and structural piping integrity of flow circulation system.

• 상하수도학회지
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• 제26권4호
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• pp.503-512
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• 2012

In Yongwon channel, its natural flow of seawater is blocked by the construction of Busan New Port including the container berth. The channel was transformed into a narrow and long one, where it is possible that ships are only allowed to pass through the north-side channel of Gyeonmado located at the point of river mouth to Songjeongcheon. In addition, Yongwon channel is approximately 100 m wide on average and 3,600 m long, and has the highest slenderness ratio (length/width = 36). So it is considered that the changes in the terrain characteristics of Yongwon channel is likely to alter the circulation of sea water, thereby changing its water quality. In this study, the bottom sediment were collected from the 48 points of the Yongwon channel and the long-term leaching characteristics were analyzed. Thus, changes in sediment and water quality were analyzed through the sediment release test to investigate the degree of contamination. The sediment release from the inside region was higher than the outer region, which is due to the pollutant that comes form the downtown area. The results of this study can be used to predict the water quality in the future and prepare the economically optimized countermeasures to improve the water quality of Yongwon channel, Busan New Port.

• 대한조선학회논문집
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• 제43권3호
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• pp.294-303
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• 2006

A surface piercing propeller (SPP) in tunnel has been proposed recently as a new propulsion system for a high speed air cavity ship. The purpose of the present study is to investigate the characteristics of the SPP in tunnel through a series of model tests. A model propulsion system is placed on a dummy body made of Acrylics. The tunnel is divided into two regions by a guide vane extending from the inlet to the center of the propeller shaft. Air has been supplied from an air nozzle placed at the bottom of the dummy body and the changes in propeller performances caused by the air flow are investigated. The measurements are done for open water and in-tunnel conditions, both for fully and partially submerged propeller. The influence of the guide vane configurations on the propeller performance is also studied. The experiments are performed at the variable pressure circulation water channel of Inha University

• 대한조선학회 특별논문집
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• 대한조선학회 2007년도 특별논문집
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• pp.107-117
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• 2007

A surface piercing propeller (SPP) in tunnel has been proposed recently as a new propulsion system for a high speed air cavity ship. The purpose of the present study is to investigate the characteristics of the SPP in tunnel through a series of model tests. A model propulsion system is placed on a dummy body made of Acrylics. The tunnel is divided into two regions by a guide vane extending from the inlet to the center of the propeller shaft. Air has been supplied from an air nozzle placed at the bottom of the dummy body and the changes in propeller performances caused by the air flow are investigated. The measurements are done for open water and in-tunnel conditions, both for fully and partially submerged propeller. The influence of the guide vane configurations on the propeller performance is also studied. The experiments are performed at the variable pressure circulation water channel of Inha University.

• 한국유체기계학회 논문집
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• 제7권1호
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• pp.30-35
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• 2004

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. Many experiments should be safely performed to activate the utilization of the HANARO. HANARO flow simulation facility is being developed for the endurance test of reactivity control units for extended life time and the verification of structural integrity of those experimental equipments prior to loading in the HANARO. This facility is composed of three major parts; a half-core structure assembly, a flow circulation system and a support system. The flow circulation system is composed of a circulation pump, a core flow piping, a core bypass flow piping and instruments. The system is to be filled with de-mineralized water and the flow should be met the design requirements to simulate a similar flow characteristics in the core channel of the half-core structure assembly to the HANARO. This paper, therefore, presents an analytical analysis to study the flow behavior of the system. Computational flow analysis has been performed for the verification of system pressure variation through the three-dimensional analysis program with the standard $k-{\epsilon}$ turbulence model and for the verification of the structural piping integrity through the finite element method. According to the analysis results, it could be said that the design requirements and the structural piping integrity of the flow circulation system are satisfied.

• 수산해양기술연구
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• 제44권1호
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• pp.68-74
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• 2008

This study is concerned with the development of the basic planing hull form of small fishing boat in 25 knots high speed. A series of model test to determine the optimum performance hull form of actual fishing boat with 10 gross tonnage was carried out for 5 models made available planing hull form in the circulation water channel. Model test was performed with the resistance test to study the hydrodynamic characteristics of model ships and the sinkage and trim measurement to investigate the stability of model ships and also the wave pattern observation to analyze the effectiveness of model ships. As the result, the planing hull form of P-4 with deep V type bow can be derived as the best hull form with good performance especially in ship's resistance efficiency showing less residual resistance and sinkage and trim and the spray effect, etc..

• 대한토목학회논문집
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• 제37권3호
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• pp.541-547
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• 2017

용원해역은 부산신항 개발사업의 일환으로 추진된 북컨테이너부두 조성사업 및 항만 배후단지 조성사업으로 전면 해역이 매립되어 원활한 해수흐름이 차단되고 송정천 하구 지점의 견마도 북쪽 통로를 이용한 선박이동만이 가능한 좁고 긴 수로형태로 변형되었다. 따라서 용원수로에 유입되는 오염물질은 수로에 체류되어 서서히 확산되는 양상을 보일 것으로 판단된다. 본 연구에서는 용원수로 내 준설 전 후 퇴적토 용출실험을 실시한 결과 준설 후에 용출농도가 낮게 나타났으며, 그룹별(A~C) 삭감률을 산정한 결과 T-N의 삭감률은 4.6%, 18.0%, 18.6%로 나타났다. T-P의 삭감률은 24.8%, 24.2%, 44.1%로 나타났다. COD의 삭감률은 18.6%, 19.8%, 38.1%로 용원수로 내 준설 후 수질개선의 효과가 나타났으며, 준설을 통한 용원수로 내 오염원을 제어하기 위한 기초자료로 활용하고자 한다.

• 수산해양기술연구
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• 제40권2호
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• pp.104-114
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• 2004

본 연구에서는 실제 정치망 어장에서의 조류변화에 따른 어구 변형을 추정하고, 그 변형을 최소화시키며 어구의 기본 기능을 유지시키는 데 필요한 수중형상과 어구 용적을 확보할 수 있는 설계의 기본 자료를 얻기 위해 회류 수조에서 모형실험을 실시하였으며, 흐름에 따른 사개줄의 장력과 그물형상의 변화를 측정하였다. 실험에서 얻은 결과를 요약하면 다음과 같다. 1. 유속이 0.0m/s에서 0.6m/s로 변화할 때에 유속(x)에 따른 장력(y)의 실험식은 y=1814.1x+115.12 이었다. 2. 수중형상에 있어서 운동장이 흐름의 조상측인 경우에 운동장그물의 기울기는 0~79$^{\circ}$까지, 비탈 그물의 기울기는 0~56$^{\circ}$까지 변화하였고, 원통 까레 깊이 비는 제1원통 까래가 1.0~0.42까지, 제2원통 까래가 1.0~0.41까지 감소하였으며, 조하측인 원통그물의 기울기는 0~87$^{\circ}$까지 변화하였다. 3. 원통이 흐름의 조상측인 경우에 원통그물의 기울기는 0~60$^{\circ}$까지, 비탈그물의 기울기는 0~13$^{\circ}$까지 변화하였고, 원통 까래 깊이 비는 제1원통 까래가 1.0~0.27까지, 제2원통 까레가 1.0~0.15까지 감소하였으며, 유속이 0.3m/s일 때 비탈그물이 원통 입구까지 부상하고 0.5m/s일 때 원통 입구를 90% 이상 막았으며, 조하측인 운동장그물의 기울기는 0~58$^{\circ}$까지 변화하였다. 4. 각 부분의 변형을 최소화하기 위해서는 입구 및 운동장 부분에서는 힘줄의 저조시 수심 위치에 중량추를 부착하고, 운동장 바깥쪽에 이동식 부가 중량추를 부착하며, 원통에서는 제1원통의 섶장과 까래그물의 연결부에 중량추 및 이동식 부가 중량추를 부착하고, 비탈그물에 중량추를 부착하며, 제2원통에 이동식 부가 중량추를 부착하는 것이 필요할 것으로 생각된다.

• 수산해양기술연구
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• 제31권4호
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• pp.340-349
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• 1995

본 연구는 현재 국내에서 일부 사용되는 쌍끌이 중층망어구어법에서 문제점으로 지적되고 있는 망고를 보다 크게 하는 것, 망목에 뜸이 걸리는 것, 네트드럼에 감기는 어구 부피를 줄이는 것 등의 해결방법으로 카이트(kite)의 적용을 검토한 것이다. 중층망의 모형에 카이트를 부착하여 회류수조에서 모형실험을 통하여 유속에 따른 어구의 저항 및 전개성능을 비교 조사하였다. 그 결과를 요약하면 다음과 같다. 1. 유체저항은 지수함수곡선의 모양을 보여 유속이 낮을 때는 저항의 증가폭이 작지만 유속이 클 때는 저항의 증가폭이 커지며, 카이트망의 저항이 중층망의 0.68~0.72배로 작다. 2. 망고는 지수함수곡선의 모양으로 감소하는 양상을 보이며, 유속 1.3m/sec 이하에서는 카이트망의 망고가 중층망보다 작지만 1.5m/sec 이상에서는 크며, 유속이 커질수록 그 차이도 커진다. 망폭은 유속 2.0m/sec 이하에서는 유속이 커짐에 따라서 다소 커지나 그 이상에서는 거의 같으며, 카이트망과 중층망은 거의 같다. 3. 망구모양은 모두 유속이 커짐에 따라서 납작해지는 타원형모양을 이루며, 망구면적은 유속이 커짐에 따라서 지수함수곡선의 형태로 작아진다. 여과량은 로그함수의 곡선 형태를 보이고 있는데, 유속 1.3m/sec 이하에서는 카이트망의 여과량이 중층망보다 적지만, 1.5m/sec에서는 카이트망의 여과량이 중층망보다 약 3%, 2.0m/sec에서는 약 11%, 2.5m/sec에서는 약 16% 더 많다