• 한국군사과학기술학회지
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• 제14권3호
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• pp.532-537
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• 2011

This paper describes the development of SPH(Smooth Particle Hydrodynamics) scheme and integration into the multi-material shock physics code(ExLO) for the purpose of the application to the extreme large deformation problems. SPH numerical scheme has been extended into the fluid dynamics and the high-speed impact events, such as space structure protection against space debris and meteorite catering. Like other hydrocodes, SPH scheme also solves the conservation equations with the constitutive equation including equation of state. The benchmark problem, Taylor-Impact test, was simulated and the predictions show good agreements with both the published numerical data and experimental data. Currently, the contact treatment between materials is under development.

• 산업기술연구
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• 제9권
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• pp.3-19
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• 1989

Shoreline have been changed from time immemorial continuously, three-quarters of the population of the world live by the sea. It is not too much to say that all of us who live in Han penisular live by coastal zone because we can reach in the beach within only for hours. In this way effectual use and menagement of coastal zone is very importent problems in side of protection of marine resources as well as land use. But it has problems which change of shoreline have to be surveyed and to be predictived. This study the pattern and characteristics of the East sea coast including investigations of the shoreline changes of the East sea. This report gives a description of the method for implementing the seawall boundary condition in the shoreline change numerical model. Such analytical solutions can provide a simple and economical means to make a quick qualitative evaluation of shoreline response under a wide range of environmental and engineering conditions.

• 대한조선학회논문집
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• 제48권1호
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• pp.23-32
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• 2011

Numerical analysis of hydrodynamic performance of a movable submerged breakwater was carried out as an eco-friendly marine structure for coastal and harbor protection. Using boundary elements method with two-dimensional frequency-domain reflection and transmission coefficients and wave forces acting on the submerged flat plate were calculated with various submerged depths and respective motion allowable modes. The movable breakwater was found to be more efficient in wave-blocking than the fixed structure. Variation of reflection coefficients was significantly influenced by vertical motion of the body.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.79-81
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• 2003

This paper presents development and testing of a new numerical spectral domain algorithm devoted to blocking unsuccessful automatic reclosing onto permanent faults and the fault distance calculation. The arc voltage amplitude and the fault distance are calculated from the fundamental and third harmonics of the terminal voltages and currents phasors. From the calculated arc voltage amplitude it can be concluded if the fault is transient arcing fault or permanent arcless fault. If the fault is permanent automatic reclosure should be blocked. The algorithm can be applied for adaptive autoreclosure, distance protection, and fault location. The results of algorithm testing through computer simulation are given.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.217-219
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• 2004

The second harmonic component could be decreased by magnetizing inrush when there have been changes to the material of the iron core or its design methodology. The higher the capacitance of the high voltage status and underground distribution, the more the differential current includes the second harmonic during the occurrence of an internal fault. Therefore, the conventional second harmonic-restrained RDR needs modification. This paper describes an advanced numerical algorithm that utilizes terminal voltage, differential current harmonics, harmonic ratio, and flux-differential current slope. Based on the results of testing with WatATP99 simulation data, the proposed algorithm was proven to be faster and more reliable.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2007년도 추계학술논문발표회 논문집
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• pp.363-368
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• 2007

• 한국가스학회:학술대회논문집
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• 한국가스학회 2004년도 추계학술발표회 논문집
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• pp.138-144
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• 2004

• 한국화재소방학회논문지
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• 제22권3호
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• pp.188-193
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• 2008

높이 1m의 수직벽면에서 3g/m^2-s$로 연소하는 프로판 수직벽 화재에 대한 수치모사를 수행하였다. 본 연구의 목적은 자연대류에서의 검증결과를 확인하고, 수직벽 화재의 수치모사의 결과를 이전의 연구와 비교하는 것이다 C_s=0.2$일 때 유동이 층류 경계층으로 나타났지만, C_s=0.1$일 때는 난류 경계층임을 확인하였다. z 방향 속도로부터 자연대류에서와 마찬가지로 난류혼합이 부족한 것으로 나타났고, 온도와 속도의 분포가 실험 및 이전의 시뮬레이션과 비교적 잘 일치하였다. 특히 x 방향 속도가 실험과 매우 잘 일치함으로써 경계층으로 공기유입이 잘 예측됨을 알 수 있었다.

• 한국화재소방학회논문지
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• 제28권4호
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• pp.29-34
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• 2014

본 연구에서는 구획화재의 연구에 적용되는 환기 변수에 근거한 상사 법칙의 유효성을 평가하기 위해 실규모 및 2/5 축소 구획에 대한 화재를 FDS를 이용하여 모사하고 기존의 실험 및 해석 결과간의 상호 비교 분석을 수행하였다. 상층부 주요 위치에서의 온도에 대한 실험 결과를 근거로 수치해석 모델의 유효성을 확보하였다. 구획 내부의 온도 및 농도 분포와 구획 출구에서의 속도 분포 등에 대한 다양한 특성에 대한 분석을 통해 축소 법칙의 유효성을 평가하였다. 실규모 및 축소 구획에 대한 화재 해석 결과를 비교할 때, 구획 내부 유동 형태 및 화염의 분출 거동, 구획 내부 수직 온도 분포 등의 특성에 대해서 유사한 결과를 보여주었다.

• Design & Manufacturing
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• 제14권2호
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• pp.28-33
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• 2020

Recently, as the income level and quality of life have improved, the desire for a pleasant environment has increased, and a deodorization plan is required through thorough prevention and diffusion of odorous substances in waste treatment facilities recognized as hateful facilities, appropriate collection, and selection of the right prevention facilities. In this study, a waste disposal facility was modeled and computerized analysis for odor and ventilation analysis was conducted. Numerical analysis of the waste treatment facility was performed at the size of the actual plant. CATIA V5 R16 for numerical model generation and ANSYS FLUENT V.13 for general purpose flow analysis were used as analysis tools. The average air-age of the internal was 329 seconds, and the air-flow velocity was 0.384m/s. The odor diffusion analysis inside the underground pump room showed congestion-free air circulation through streamline distribution and air-age distribution. This satisfies the ASHRAE criteria. In addition, the results of diffusion analysis of odorous substances such as ammonia, hydrogen sulfide, methyl mercaptan and dimethyl sulfide were all expected to satisfy the regulatory standards. Particularly in the case of the waste loading area, the air-flow velocity was 0.297m/s, and the result of meeting the regulatory standards with 0.167ppm of ammonia, 0.00548ppm of hydrogen sulfide, 0.003ppm of methyl mercaptan, and 0.003ppm of dimethyl sulfide was found.