• Title/Summary/Keyword: Code validation

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Design of Software GPS L2 Civil Signal Generator (ICCAS 2003)

  • Seo, Sam-Suk;Cho, Deuk-Jae;Lee, Sang-Jeong
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2632-2635
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    • 2003
  • This paper designs a software signal generator for the new GPS L2 civil signal. The CM/CL code and the message structure of L2CS described in GPS ICD PPIRN-200C-007 are used in designing the signal generator. The output of the GPS signal generator is designed as the sampled IF data with the sampling frequency 5.7MHz and stored in the binary data format. By analyzing both the spectrum characteristics of the output signal and the correlation properties of the CM/CL code, the validation of the designed GPS signal generator is shown. It should be mentioned that the modeling of the GPS satellite constellation and the error sources remains for implementing the software space segment of GPS.

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Numerical Flow Analysis of Ducted Marine Propeller with Pre-Swirl Guidevane (전치 가이드베인을 가지는 수중 덕트 프로펠러 주위의 전산 유동 해석)

  • Yu Hye-Ran;Jung Young-Rae;Park Warn-Gyu
    • Journal of computational fluids engineering
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    • v.9 no.2
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    • pp.62-69
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    • 2004
  • The present work solved 3D incompressible RANS equations on a rotating, multi-blocked grid system to efficiently analyze ducted marine propulsor with the interaction of propeller guidevane and annular duct. To handle the interface boundary between the guidevane and the propeller, a sliding multiblock technique based on the cubic spline interpolation was applied. To validate the present code, a turbine flow was simulated and the time-averaged pressure coefficients were compared with experiment. After the code validation, the flowfield around a ducted marine propeller with pre-swirl guidevane was simulated.

Reactivity Feedback Models for Safety Performance of Metal Core

  • Han, Chi-Young;Kim, Jong-Kyung;Dohee Hahn
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.05a
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    • pp.542-547
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    • 1997
  • In the SSC(Super System Code), the reactivity feedback models of the Doppler effect and fuel axial expansion were modified to evaluate the safety performance of the metal-fueled core. The core radial expansion model was developed and implemented into the code as well. The transient analyses have been performed by the modified SSC for UTOP, ULOHS, ULOF/LOHS, and UTOP/LOF/LOHS events for one of the core design options being considered. Analysis results shows that the reactivity feedbacks can provide an inherent shutdown capability in response to key anticipated events without scram. Development of other reactivity feedback models and validation of these models against experimental data would make the SSC suitable for the assessment of the metal-fueled core safety performance.

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3-D Numerical analysis of flow and temperature field in the cabin of the automobile with defrost nozzle discharged air (Defrost nozzle의 영향을 고려한 3차원 승용차 실내 유동 및 온도 해석)

  • Kang Kyu-Tae;Bae In-Ho;Hwang Ji-Eun;Park Warn-Gyu
    • 한국전산유체공학회:학술대회논문집
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    • 2001.10a
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    • pp.31-36
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    • 2001
  • The velocity and temperature profiles in the cabin of the automobile affect greatly to the comfort of the passenger. In this paper, the three dimensional flow and temperature analysis in the cabin of the automobile which is geometrically complicated was performed to investigate and predict the velocity and temperature profile. The three dimensional Navier-Stokes code used in this case was validated by performing of a 1/5 experimental scale model vehicle flow anal)rsis successfully. The temperature field of cavity was analyzed for Energy-equation code validation. The comparison of the results are made with the polished computational data and give a coincided one.

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NUMERICAL ANALYSIS OF THERMAL FLOW OF CABIN INTERIOR AND DE-ICING ON AUTOMOBILE GLASS (자동차 내부 열유동해석 및 전방유리면의 해빙 전산해석)

  • Song D. W.;Park W. G.;Jang K. L.
    • 한국전산유체공학회:학술대회논문집
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    • 2005.10a
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    • pp.75-80
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    • 2005
  • The present work was undertaken to numerically analyze the defrosting phenomena of windshield glass. In order to analysis the phase change from frost to water on windshield glass by discharging hot air from a defroster nozzle, the flow and the temperature field of the cabin interior, the heat transfer through the windshield glass, and the phase change of frost should be solve simultaneously. In the present work, the flow field was obtained by solving 3-D incompressible Navier-Stokes equations, and the temperature field was computed from the incompressible energy equation. The phase change process was solved by the enthalpy method. For the code validation, the temperature and the phase change of the driven cavity were calculated. The calculation showed a good agreement with other numerical results. Then, the present code was applied to the defrosting problem of a real automobile, and a good agreement with the experimental data was also obtained.

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A Numerical Model for Atomization of an Impinging Spray on the Wall (벽면에 충돌하는 분무의 미립화에 관한 수치적 모델)

  • Joh, Mi-Ok;Huh, Kang-Y.
    • Journal of ILASS-Korea
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    • v.2 no.1
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    • pp.36-45
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    • 1997
  • A spray-wall impingement model for fuel sprays is proposed and implemented as a module into the KIVA-POSTECH code. The model is based on the single droplet experiments. The droplet behaviors after impingement are determined from experimental correlations. Different behaviors of impinged droplets depend on the wall temperature and the critical temperature of the fuel. Fuel film formation is taken into account so that the model can be applicable to any wall temperature and injection conditions. Computational results on a normal and on inclined wall are in good agreement for the spray shape and penetration. More validation against experiments and development of the heat transfer model are needed for further improvement.

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DEVELOPMENT OF POINT KERNEL SHIELDING ANALYSIS COMPUTER PROGRAM IMPLEMENTING RECENT NUCLEAR DATA AND GRAPHIC USER INTERFACES

  • Kang, Sang-Ho;Lee, Seung-Gi;Chung, Chan-Young;Lee, Choon-Sik;Lee, Jai-Ki
    • Journal of Radiation Protection and Research
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    • v.26 no.3
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    • pp.215-224
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    • 2001
  • In order to comply with revised national regulationson radiological protection and to implement recent nuclear data and dose conversion factors, KOPEC developed a new point kernel gamma and beta ray shielding analysis computer program. This new code, named VisualShield, adopted mass attenuation coefficient and buildup factors from recent ANSI/ANS standards and flux-to-dose conversion factors from the International Commission on Radiological Protection (ICRP) Publication 74 for estimation of effective/equivalent dose recommended in ICRP 60. VisualShieid utilizes graphical user interfaces and 3-D visualization of the geometric configuration for preparing input data sets and analyzing results, which leads users to error free processing with visual effects. Code validation and data analysis were performed by comparing the results of various calculations to the data outputs of previous programs such as MCNP 4B, ISOSHLD-II, QAD-CGGP, etc.

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NUMERICAL CODE DEVELOPMENT OF THE MULTIPHASE FLOW AROUND AN UNDERWATER VEHICLE UNDER SUBMARINE WAKE. (후류중에 있는 수중운동체의 캐비테이션 유동 현상 및 유체력 변화 해석 코드 개발)

  • Park, S.I.;Ha, C.T.;Park, W.G.;Lee, K.C.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.115-121
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    • 2010
  • Cavitating flow is widely shown in many engineering systems, such as marine propellers, pump impellers, nozzles, injectors, torpedoes, etc. The present work focuses on the numerical analysis of the multiphase flow around the underwater vehicle which was launched from a submarine. The governing equation is the Navier-Stokes equation with a homogeneous mixture mode. The multiphase flow solver uses an implicit preconditioning scheme in curvilinear coordinate. For the code validation, the results from the present work are compared with the existing experimental and numerical results, and a reasonably good agrements are obtained. The multiphase flow around an underwater vehicle is simulated which includes submarine wake effects.

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PREDICTION OF AERODYNAMIC CHARACTERISTICS AND BODY VORTICES OVER SUPERSONIC MISSILES (초음속 유도탄의 동체 와류 예측 및 공력 특성 분석)

  • Yoon, S.H.;Kim, Chang-Am;Hur, K.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.308-314
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    • 2010
  • In this study, NASA test model with four cruciform fins is utilized to validate the in-house code. Sur face pressure distribution and aerodynamic coefficients are compared with experimental data. Through extensive validation work, it is verified that the code has capability to predict aerodynamic characteristics of missile configuration. In inviscid analysis through a relatively low computational time, analysis result close to experimental data can be confirmed. However, at high angle of attack more than 20 degree, the accuracy of analysis is gradually decreased due to massive separation. In addition, it has been seen that Reynolds number, turbulence model and numerical method have effects on body vortices and aerodynamic characteristics.

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AN ANALYSIS OF THE AERODYNAMIC CHARACTERISTICS OF A T-50 CONFIGURATION USING A PANEL CODE AND ITS VALIDATION (패널코드를 이용한 T-50 형상의 공력특성 예측 및 검증)

  • Park, S.W.;Kim, D.J.;Je, S.E.;Myong, R.S.;Cho, T.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2006.10a
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    • pp.131-135
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    • 2006
  • The aerodynamic characteristics of a T-50 aircraft configuration are investigated by a subsonic panel method. Panel methods are best applicable to the lifting surfaces such as wings and airfoils. Source and doublets are used in the present code as a basic singularities of the panel technique. The panel method is first assessed by applying it to several benchmark problems for which other solutions and experimental data are available, such as a swept wing and wing body configuration. The prediction results are compared with experimental data and show good agreement in all cases considered. Finally, the method is applied to a T-50 aircraft configuration and excellent agreement with flight test data in lift coefficients is found.

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