• Title/Summary/Keyword: 정지유체

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The Prediction of Hydrodynamic Forces Acting on Ship Hull Undergoing Lateral Berthing Maneuver Using CFD (CFD을 이용한 선박 접이안시 유체력 추정에 관한 연구)

  • 이윤석;정겸광행;공길영;김순값;이충로
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2003.05a
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    • pp.132-138
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    • 2003
  • In order to evaluate properly ship motion relating to the berthing maneuver, the hydrodynamic forces acting on ship hull in berthing maneuver need to be estimated rightly. CFD has been employed for time-domain simulation of transient flow induced by Wigley model moving laterally from rest in shallow water. The numerical solutions successfully captured not only the characteristics of the transitional hydrodynamic forces but also some interesting features of the flow field around a berthing ship according to the water depth. In this paper, the consideration is carried out on the approximate formula based on the CFD results, which can estimate hydrodynamic forces especially lateral drag coefficient starting from the rest to the uniform movement.

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THERMAL BALANCE MODELLING AND PREDICTION FOR A GEOSTATIONARY SATELLITE (정지궤도 위성의 열평형 시험 모델링 및 예비 예측)

  • Jun, Hyoung-Yoll;Kim, Jung-Hoon
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.142-147
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    • 2009
  • COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean and meteorological observations. It will be tested under vacuum condition and very low temperature in order to verify thermal design of COMS. The test will be performed by using KARI large thermal vacuum chamber, which was developed by KARI, and the COMS will be the first flight satellite tested in this chamber. The purposes of thermal balance test are to correlate analytical model used for design evaluation and predicting temperatures, and to verify and adjust thermal control concept. KARI has plan to use heating plates to simulate space hot condition especially for radiator panels such as north and south panels. They will be controlled from 90K to 273K by circulating GN2 and LN2 alternatively according to the test phases, while the shroud of the vacuum chamber will be under constant temperature, 90K, during all thermal balance test. This paper presents thermal modelling including test chamber, heating plates and the satellite without solar array wing and Ka-band reflectors and discusses temperature prediction during thermal balance test.

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DEVELOPMENT OF THERMAL ANALYSIS PROGRAM FOR HEAT PIPE INSTALLED PANEL OF GEOSTATIONARY SATELLITE (히트 파이프가 장착된 정지궤도 위성 패널 열해석 프로그램 개발)

  • Jun, Hyoung-Yoll;Kim, Jung-Hoon;Han, Cho-Young;Chae, Jong-Won
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.416-421
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    • 2010
  • The north and south panel of a geostationary satellite are used for radiator panels to reject internal heat dissipation of electronics units and utilize several heat pipe networks to control the temperatures of units and the satellite within proper ranges. The design of these panels is very important and essential at the conceptual design and preliminary design stage so several thousands of nodes of more are utilized in order to perform thermal analysis of panel. Generating a large number of nodes(meshes) of the panel takes time and is tedious work because the mesh can be easily changed and updated by locations of units and heat pipes. Also the detailed panel model can not be integrated into spacecraft thermal model due to its node size and limitation of commercial satellite thermal analysis program. Thus development of a program was required in order to generate detailed panel model, to perform thermal analysis and to make a reduced panel model for the integration to the satellite thermal model. This paper describes the development and the verification of panel thermal analysis program with ist main modules and its main functions.

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DEVELOPMENT OF THERMAL ANALYSIS PROGRAM FOR GEOSTATIONARY SATELLITE PANEL (정지궤도위성 위성체패널 열해석 프로그램 개발)

  • Jun, Hyoung-Yoll;Kim, Jung-Hoon;Han, Cho-Young;Chae, Jong-Won
    • Journal of computational fluids engineering
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    • v.15 no.3
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    • pp.66-72
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    • 2010
  • The north and south panel of a geostationary satellite are used for radiator panels to reject internal heat and utilize several heat pipe networks to control the temperatures of units and the main structures of satellite within proper ranges. The design of these panels is very important and essential at the conceptual design and preliminary satellite design stage, so several thousands of nodes or more are utilized in order to perform detailed thermal analysis of panel. Generating a large number of panel nodes takes time and is tedious work because the nodes can be easily changed and updated by locations of units and heat pipes. Also the detailed panel model can not be integrated into spacecraft thermal model due to its node size and limitation of commercial satellite thermal analysis program. Thus development of a program was required to generate a detailed panel model, to perform thermal analysis and to make a reduced panel model for the integration to the satellite thermal model. This paper describes the development and the verification of the panel thermal analysis program with its main modules and functions.

Hydrodynamic Forces and Maneuvering Characteristics of Ships at Low Advance Speed (저속시 선체에 작용하는 조종유체력 및 조종성능에 관한 연구)

  • Kyoung-Ho Sohn
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.3
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    • pp.90-101
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    • 1992
  • Some practical methods have already been proposed for predicting the characteristics of ship manoeuvring motions at relatively high advance speed. However, these methods can hardly be applied to motions of ships in starting, stoppint, backing and slow steaming conditions, even though such extensive motions are of vital importance from a safety point of view particularly in harbour areas. The method presented here aims at predicting the characteristics of ship manoeuvring at low advance speed, which covers starting, stopping, backing and slow steaming conditions. The force mathematical models at large angles of incidence to the hull as well as under the tilde range of propeller operations are formulated. Simulations of various manoeuvres at low advance speed are carried out for two types of merchant ship, i.e. a LNGC and a VLCC. Comparisons between simulations and corresponding full-scale measurements or free-running model tests provide a first verification of the proposed mathematical models.

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Computational analysis of coupled fluid-structure for a rotor blade in hover (정지 비행하는 로터 블레이드의 전산 유체-구조 결합 해석)

  • Kim, Hae-Dong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.12
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    • pp.1139-1145
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    • 2008
  • numerical study on the coupled fluid-structure for a rotor blade in hover was conducted. Computational fluid dynamics code with enhanced wake-capturing capability is coupled with a simple structural dynamics code based on Euler-Bernoulli's beam equation. The numerical results show a reasonable blade structural deformation and aerodynamic characteristics.

Seismic Analysis of Rack Structure with Fluid-Structure Interaction (유체와 구조물의 연성을 고려한 rack 구조물의 내진해석)

  • Kim, S.J.;Lee, Y.S.;Ryu, C.H.;Yang, K.H.;Jung, S.H.
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.465-470
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    • 2001
  • In this study, the seismic analysis of rack structure with fluid-structure interaction is performed through use of the Finite Element Method(FEM) code ANSYS. Fluid-structure interaction can specify in terms of an hydrodynamic effect which is defined as the added mass per unit length divided by the area of the cross section. Using the Floor Response Spectrum(FRS) obtained through the time-history analysis, modal analysis and seismic analysis under Operating Basis Earthquake(OBE) and Safe Shutdown Earthquake(SSE) condition is carried out. The fluid-structure interaction effects on the rack structure are investigated.

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