• Title/Summary/Keyword: MMU

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An experimental study on the Free stream turbulence of Floating body with vertical plate (연속부착된 수직평판을 갖는 부유구조물 후류의 자유유동 난류강도에 대한 실험적연구)

  • Kim, Ho;Oh, Kyoung-Gun;Gim, Ok-Sok;Lee, Gyoung-Woo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2007.12a
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    • pp.125-126
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    • 2007
  • In this paper, the floating body with vertical plate is introduced with a study on the flow patterns and characteristics in around the floating body by using 2 frame particle tracking method. This paper introduce an analysis method to predict the characteristics if flow around the neighboring fields if Floating Body with vertical plate in order to investigate a high performance model. Flow visualization has conducted in a drcu1ating water channel by a high speed camera and etc. Flow phenomena according to turbulence intensity distribution and flow separation around the floating body with vertical plate were obtained by two-dimensional PIV system.

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Engineering Model Design and Implementation of Mass Memory Unit for STSAT-2 (과학기술위성 2호 대용량 메모리 유닛 시험모델 설계 및 구현)

  • Seo, In-Ho;Ryu, Chang-Wan;Nam, Myeong-Ryong;Bang, Hyo-Choong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.11
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    • pp.115-120
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    • 2005
  • This paper describes the design and implementation of engineering model(EM) of Mass Memory Unit(MMU) for Science and Technology Satellite 2(STSAT-2) and the results of integration test. The use of Field-Programmable Gate Array(FPGA) instead of using private electric parts makes a miniaturization and lightweight of MMU possible. 2Gbits Synchronous Dynamic Random Access Memory(SDRAM) module for mass memory is used to store payload and satellite status data. Moreover, file system is applied to manage them easily in the ground station. RS(207,187) code improves the tolerance with respect to Single Event Upset(SEU) induced in SDRAM. The simulator is manufactured to verify receiving performance of payload data.

An Experimental Study on Flow control around Foil with Coanda effect (콴다효과를 이용한 익 주위의 유동제어에 관한 실험적 연구)

  • Oh, Kyoung-Gun;Cho, Dae-Hwan;Lee, Gyoung-Woo;Ko, Jae-Yong
    • Proceedings of KOSOMES biannual meeting
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    • 2006.11a
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    • pp.65-69
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    • 2006
  • The flow around a foil with water jet was investigated using the two-frame PIV(CACTUS 3.1) system. After separation, unsteady recirculation & reattachment region was shown a result at reading edge. Separation area was decreased to 1/3 more by waterjet system with coanda effect. Angle of attack and water jet velocity was a variable in the experiment. Each parameters was controlled to $0^{\circ}\sim35^{\circ}$ and $0[m/s]\sim9.2[m/s]$. The separation of flow appearanced at first when the angle of attack is $17^{\circ}\sim18^{\circ}$, However, according to grew up of velocity, beginning of the separation was delayed. In this experiment, vortex and separation region was disappeared by blown when each parameters are low level, and separation controlled more certainly.

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PIV Applications for Flow Analysis of Floating Breakwater with double barriers (이흘수판형 부소파제 주위의 유동해석을 위한 PIV 적용)

  • Kim, Ho;Cho, Dae-Hwan;Lee, Gyoung-Woo;Gim, Ok-Sok
    • Proceedings of KOSOMES biannual meeting
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    • 2006.11a
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    • pp.53-58
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    • 2006
  • Along with the development of costal engineering, various type of breakwaters have been built. The main purpose of breakwaters are to provide harbour protection against waves, to stabilize beaches against erosion due to large wave action, and to provide for temporary wave protection for installation on or under water surface. This paper an application example of PIV system for analyzing the flow of Floating Breakwater with double barriers. We introduce an analysis method to predict the characteristics of flow around the neighboring fields of Floating Breakwater with double barriers in order to develop a high performance model. Flow visualization has conducted in circulating water channel by a high speed camera and etc. Flowing phenomenon according to velocity distribution and flow separation around the breakwater with double barriers were obtained by 2-D PIV system.

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Nonlinear Potential Flow Analysis for the Hull with a Transom Stern (트랜섬 선미를 가지는 선형의 비선형 포텐셜 유동해석)

  • Choi, Hee-Jong;Lee, Gyoung-Woo;Shin, Sung-Chul;Youn, Sun-Dong;Yang, Jun-Mo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.29 no.1
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    • pp.41-46
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    • 2005
  • In this paper, the flow phenomena and free surface wave pattern around the hull with a transom stern advancing on the free surface in steady state had been studied and the numerical analysis program had been developed using Rankine source panel method based on potential flow analysis in which the non-linearities of the free surface boundary conditions had been fully satisfied. To verify the validity of the developed program the numerical calculations for Athena hull and KCS(KRISO container ship) hull had been performed and the results of the numerical computation had been compared with the ones of the model test experiment.

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Study for the Development of an Optimum Hull Form using SQP (SQP법을 이용한 최적선형개발에 대한 연구)

  • Choi, Hee-Jong;Lee, Gyoung-Woo;Kim, Sang-Hoon;Kim, Ho
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.29 no.1
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    • pp.47-53
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    • 2005
  • This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP(sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using NURBS(Non-Uniform Rational B-Spline) surface patches. To verity the validity of the developed program the numerical calculations for Wigley hull and Series 60(C${_B}$=0.6) hull had been performed and the results obtained after the numerical calculations had been compared with the original hulls.

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Vortex Flow Analisys around the Floating Body with Vertical Plate (연속부착된 수직평판을 갖는 부유구조물 주위의 와유동 해석)

  • Kim, Ho;Lee, Gyoung-Woo;Cho, Dae-Hwan;Gim, Ok-Sok
    • Proceedings of KOSOMES biannual meeting
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    • 2007.05a
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    • pp.161-168
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    • 2007
  • In this paper, the floating body with double barriers is introduced with a study on the flow patterns and characteristics in around the floating body by using 2 frame p article tracking method. This paper introduce an analisys method to predict the characteristics of flow around the neighbording fields of Floating Body with double barriers in order to investigate a high performance model. Flow visualization has conducted in a circulating water channel by a high speed camera and etc. Flow phenomena according to velocity distribution and flow separation around the floating body with double barriers were obtained by two-dimensional PIV system.

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A Study of PIV Analysis around 2-Dimensional Foil with Blowing (물분사장치를 이용한 2차원 익 주위의 PIV 해석에 관한 연구)

  • Oh, Kyoung-Gun;Cho, Dae-Hwan;Lee, Gyoung-Woo;Ko, Jae-Yong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.45-49
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    • 2006
  • The flow around a foil with waterjet was investigated using the two-frame PIV(CACTUS 3.1) system. After separation, unsteady recirculation & reattachment region was shown as a result at reading edge. Separation area was decreased to 1/3 more by waterjet system with coanda effect. Angle of attack and waterjet velocity was a variable in the experiment. Each parameters was controlled to $0^{\circ}{\sim}35^{\circ}$ and 0[m/s]${\sim}$9.2[m/s]. The separation of flow appearanced at first when the angle of attack is $17^{\circ}{\sim}18^{\circ}$. However, according to grew up of velocity, beginning of the separation was delayed. In this experiment, vortex and separation region was disappeared by blown when each parameters are low level, and separation controlled more certainly.

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Hydrodynamic-Structural Response Coupling Analysis to a Rectangle Floating Structures (장방형 부유구조물에 대한 동유체력-구조응답 특성)

  • Oh, Young-Cheol;Gim, Ok-Sok;Ko, Jae-Yong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.6
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    • pp.577-583
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    • 2012
  • Structures floating in the ocean experience various kinds of external loads, among which wave load is considered as determining factor in structural design. Its relative size compared with wavelength may be used to classify whether the structure is relatively small or large. Traditionally, the small structures are assumed to have little diffraction and the wave loads on large structure are usually calculated by only considering inertia force according to diffraction. In this paper, rectangular floating structures usually used in the ocean, river, and lake are used to find the relationship between hydrodynamic forces and its structural response.

Put Investigation on the energy saving method using inverter driving for cooling pump at MMU training ship (인버터 구동방식에 의한 실습선 냉각수 펌프의 에너지 절감 방법)

  • Lim, Myeong-Hwan;Ahn, Byong-Won;Kim, Bu-Gi
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.6
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    • pp.880-885
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    • 2009
  • The ships have a lot of electric machinery needed to supply electricity from the moment of launching coming out of dry dock to docking at jetty. Thus, the ships always have to use alternator and electric machinery that has low efficiency under the low load. Many government service ships like the MMU training ship have been spending lots of time at jetty rather than sailing at sea. These ships are operated under the condition of low load due to the operation of basic machinery at jetty and electric machineries are driven with the status of low efficiency. This paper would suggest the energy saving method for these ships. The investigation describes that shore connection is a great asset to these ships and that the flow rate control by adjusting revolution with the adoption of inverter is better than flow rate control by using throttle valve to save energy. The result is based on the investigation of cooling pump at MMU training ship.