• Title/Summary/Keyword: 이론전산학

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Transonic/Supersonic Nonlinear Aeroelastic Analysis of a Complete Aircraft Using High Speed Parallel Processing Technique (고속 병렬처리 기법을 이용한 전기체 항공기 형상의 천음속/초음속 비선형 공탄성 해석)

  • Kim, Dong-Hyun;Kwon, Hyuk-Jun;Lee, In;Kwon, Oh-Joon;Paek, Seung-Kil;Hyun, Yong-Hee
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.8
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    • pp.46-55
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    • 2002
  • A nonlinear aeroelastic analysis system in transonic and supersonic flows has been developed using high speed parallel processing technique on the network based PC-clustered machines. This paper includes the coupling of advanced numerical techniques such as computational structural dynamics (CSD), finite element method (FEM) and computational fluid dynamics (CFD). The unsteady Euler solver on dynamic unstructured meshes is employed and coupled with computational aeroelastic solvers. Thus it can give very accurate engineering data in the structural and aeroelastic design of flight vehicles. To show the great potential of useful application, transonic and supersonic flutter analyses have been conducted for a complete aircraft model under developing in Korea.

Performance Analysis of the Pintle Thruster Using 1-D Simulation -I : Steady State Characteristics (1-D 시뮬레이션을 활용한 핀틀추력기의 성능해석 -I : 정상상태 특성)

  • Kim, Jihong;Noh, Seonghyeon;Huh, Hwanil
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.4
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    • pp.304-310
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    • 2015
  • Pintle thrusters use pintle stroke to change nozzle throat area, and this controls thrust. Using MATLAB, one-dimensional simulation has been investigated and the results are compared to those of cold flow tests and computational fluid dynamics for the pintle thruster of Chungnam National University. The prediction based on one-dimensional flow theory shows good agreement with measurements for chamber pressure, but deviates for thrust, partly because of nozzle wall separation. Computational results show that nozzle wall separation occurs at an early stage of nozzle expansion, near the design nozzle throat, for the course of pintle strokes. Empirical thrust prediction incorporates nozzle wall separation, and thus 1-D simulation using empirical thrust prediction showed good results for an early stage of pintle stroke.

Thickness Evaluation of Pipeline Using Density Profile on a Radiograph (방사선투과필름에서 Density Profile을 이용한 배관의 두께 평가)

  • Lee, Sung-Sik;Jang, Byoung-Gyu;Kim, Young-H.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.5
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    • pp.483-489
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    • 2002
  • The computer simulation has been done for non-insulated and insulated pipes which are vacant or half filled with liquid. The simulation results showed that the density profile on the radiography is continuous and symmetrical around the center of pipe in the case of vacant pipe. On the other hand the density profiles are not symmetrical and depend on geometrical setting for radiography in the case of half filled pipes. Finally, experimental testing on a non-insulated carbon steel pipe with artificial notches of different depth is carried out using Ir-192 and industrial film. Comparing the measured density profile on the radiograph to the calculated one, it has been shown that it is possible to evaluate thickness variation by measuring density profile on a radiograph.

Development of Prediction Program of Added Resistance Due to Waves at the Towing Condition of a Disabled Ship Using ISO 15016 Analysis Method (ISO 15016 해석법에 의한 사고선박 예인 시 파랑 중 부가저항 추정 프로그램 개발)

  • Choi, Hyuek-Jin;Kim, Eun-Chan;Lee, Seung-Guk
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.19 no.2
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    • pp.159-164
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    • 2016
  • It is one of the important processes to predict the resistance of the towed ship when towing a disabled ship on the sea. Besides the basic resistance of hull itself, there are various added resistance, especially the added resistance due to waves can be considered one of the biggest component. In this paper, the algorithm which predict the added resistance due to waves of a disabled ship by theoretical analysis method of ISO 15016 standard was established, and realized as a computer program. The calculated result for an example ship was compared with existing standard one, and it is considered that this algorithm and computer program are appropriate to use for predicting the resistance and towing force of the disabled ship actually.

The Study of Advanced Propeller Blade for Next Generation Turboprop Aircraft -Part I. Aerodynamic Design and Analysis (차세대 터보프롭 항공기용 최신 프로펠러 블레이드 연구 -Part I. 공력 설계 및 해석)

  • Choi, Won
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.12
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    • pp.1017-1024
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    • 2012
  • The aerodynamic design and analysis on advanced propeller with blade sweep was performed for recent turboprop aircraft. HS1 airfoil series are selected as a advanced propeller blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. Propeller geometry is generated by varying chord length and pitch angle at design point of target aircraft. Advanced propeller is designed by apply the modified chord length, the tip sweep which is based on the geometry of conventional propeller. The aerodynamic characteristics of the designed Advanced propeller were verified by CFD(Computational Fluid Dynamic) and evaluated to be properly designed.

The Performance Estimation of Rotor in Wind Fence by Rotor Analysis Solver based on Actuator Disk Model (Actuator Disk Model 기반의 로터 해석자를 사용한 방풍 구조물 내부의 로터 성능 예측)

  • Kim, Taewoo;Oh, Sejong;Kang, Hee Jung;Yee, Kwanjung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.6
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    • pp.429-439
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    • 2013
  • The purpose of current study is to develop the rotor analysis solver and perform a rotor aerodynamic analysis in the wind fence. To this end, the rotor analysis solver based on actuator disk model was employed. To consider the asymmetric effect of the rotor in the wind fence, the flapping motion analysis was conducted with blade element theory for the effective angle of attack calculation. The validation cases which are the rotor with wall and ground were accomplished by developed solver. The decrease of rotor performance by wind fence was confirmed. The wind fence configuration was suggested which guarantees more than 95% rotor performance compared with the no fence case.

The Extension and Validation of OpenFOAM Algorithm for Rotor Inflow Analysis using Actuator Disk Model (Actuator Disk 모델 기반의 로터 유입류 해석을 위한 OpenFOAM 알고리즘 확장)

  • Kim, Tae-Woo;Oh, Se-Jong;Yee, Kwan-Jung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.12
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    • pp.1087-1096
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    • 2011
  • The purpose of current study is to develop and verify the newly developed solver for analyzing rotor flow using the open-source code. The algorithm of standard solver, OpenFOAM, is improved to analyze the rotor inflow with and without fuselage. For the calculation of the rotor thrust, the virtual blade method based on the blade element method is employed. The inflow velocities on the rotor disk used to specify the effective angle of attack, have been included in the solver. The results of the current rotor inflow analysis are verified by comparing with other experimental and numerical results. It was confirmed that the modified solver provides satisfactory results for rotor-fuselage interaction problem.

Development of Design Program of Regeneratively Cooled Combustion Chamber (재생냉각 연소실 설계 프로그램 개발)

  • Cho, Won-Kook;Seol, Woo-Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.3
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    • pp.102-110
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    • 2004
  • A design code validated against the thermal analysis results of CFD and published RTE code for a regeneratively cooled combustion chamber has been developed. The major function of the code is to predict the regenerative cooling performance and stress of the chamber wall. Adopted are the empirical correlation for the evaluation of the heat transfer coefficient of hot gas and coolant, and theoretical formula for the fin effect of the channel rib. The hot-gas-side wall temperature from the present code shows 100 K difference at most compared to RTE results. It shows less than 10 % difference for the heat flux thrall through the chamber wall and hot-gas-side convective heat transfer coefficient. The major cause of the wall temperature difference is due to the underestimation of the fin effect of the channel rib.

Rupture Safety Assesment of Bipropellant Propulsion System at High Pressure Testing (이원 추진 시스템 고압 시험시의 파열 안전성 고찰)

  • Chang, Se-Myong;Han, Cho-Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.605-611
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    • 2010
  • The geostationary satellite COMS is going to be launched in 2010, and, in the series of test, there are some high-pressure tests concerning the vessel tank filled with helium gas of hundreds atmospheric pressure. In this paper, authors evaluates risk associated with accidental rupture of the test system. Two possible scenarios are considered: 1) the 310-bar helium tank ruptures at the center of the acoustic chamber, and 2) the 116-bar reduced-pressure helium tank ruptures in the test room shielded by bullet-proof glasses. Using the theory of blast wave propagation and computational simulation, the dynamics of wave reflected in a confined space is investigated for highly complex unsteady flow physics.

Study on the Free Surface Behavior Using the Lattice Boltzmann Method (격자볼츠만법을 이용한 자유수면 거동 특성 연구)

  • Jung, Rho-Taek
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.4
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    • pp.255-262
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    • 2013
  • The boltzmann equation is based on the particle distribution function while the Navire-Stokes equation based on the continuum theory. In order to simulate free surface flow, this paper used the Lattice Boltzmann Method of which is the discretized form. The detail study on the characteristics of the Lattice Boltzmann Method for the free surface simulation was investigated. The developed code was validated with the traditional dam breaking problem by tracking the front position of the water. A basic roles of density functions in the Lattice Boltzmann Method is discussed. To have an engineering applications, the simulation is also conducted the free surface behavior with an arbitrary wall geometry.