• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.605-610
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• 1996

영광 원전부지에서 미시규모 기상현상 파악, 대기확산 특성연구, 실시간 수치모델의 검증을 목적으로 국내에서 처음으로 대규모 학술목적의 야외확산실증을 수행하였다. 1996년 5월 29일과 30일 양일간 두차례 추적자방출 및 포집을 실시하였다. SODAR를 이용한 고공기상측정 결과 해륙풍현상을 발견할 수 있었으며, 추적자 농도분포 분석결과 최대 농도값이 나타나는 방향이 거리에 따라 고도별 풍향변화에 영향을 받고 있음을 발견하였다.

• Fire Science and Engineering
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• v.26 no.1
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• pp.31-37
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• 2012

This study is intended to present a computational thermal model for a residential building. As the Performance Based Design is more popular, fire-intensity and fire-load have turned out to be very important factors for building design and can be predicted through some computational work. To predict and estimate the fire properties of a residential fire, we made some numerical models of combustibles and residential building. In a bid to validate the estimate values, computational analysis results from numerical models were compared with real fire tests. For computational analysis, the Fire Dynamics Simulator (FDS) was used with Large Eddy Simulation (LES) model for turbulence. Consequently, fire-intensity was well predicted and flash-over of rooms were successfully estimated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.99-104
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• 2009

In this paper, the drop characteristic of the small aircraft landing gear of SUAV has been analyzed and performed on orifice optimal design for shock absorption efficiency. The SUAV landing gear was simple oleo pneumatic type without metering pin. The landing gear was modelled by MSC ADAMS software. Drop test evaluation was conducted to confirm the analysis model. As a result of correlation between analysis and test results, it was verified that these results were coincided with very well. After confidence review of analysis model through the correlation between test and analysis results, design parametric study was performed by using confirmed analysis model. Optimal orifice size with best efficiency have been decided in this study.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.39-39
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• 1998

본 연구는 500KW급 수평축 풍력발전기용으로 개발된 회전날개의 시제품 제작에 앞서 축소모델에 대한, 이론적으로 예측된 공력성능과 신축에 의한 공력성능을 비교 검토함으로서, 설계결과를 검증하고, 필요한 경우 설계를 보완하여 개발위험도를 최소화하기 위해 수행되었다. 시험모델의 크기는 실제의 5%로서 직경이 2.1m이며 날개의 시위길이는 0.2r/R에서 0.101m, 날개끝에서 0.043m 이고, 날개단면형 상온 FX-S-03-182이다. 블레이드의 재질은 Glass/Epoxy 복합재료로 제작되었으며, 실제 풍황을 모사하기 위해 자연풍 상태에서 실험하였다. 실험장치의 구성은 15m 높이의 타워에 회전날개와 전자브레이크 및 각종 센서를 장착하였고, 날개가 회전하기 시작하면 제동장치에 의해 부하를 주면서 토크, 회전수, 풍속 등을 각각의 센서로부터 자료획득장치를 통해 자료처리를 할 수 있도록 하였다. 실험하는 동안 풍속은 4m/s-13m/s 정도로서 시동 풍속인 4m/s와 정격풍속인 12m/s를 포함하여 회전날개의 전체적인 특성을 파악하기 용이하였고, 이론적인 예측성능과 측정된 성능을 비교 검토한 결과 비슷한 결과를 얻어 공력설계 및 해석 방법을 검증하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.217-227
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• 1992

The first and second-order reliability method(FORM and SORM) is presented using one dimensional finite difference and two dimensional finite element transport models. FORM and SORM can be used without any restrictive assumptions about the properties of the media, and the sensitivity information obtained as part of these analyses is used to identify the parameters which have major influence on the estimate of probability. The reliability analysis of transport in a one-dimensional domain is used to test the robustness of the reliability code and to evaluate the accuracy of the reliability method. A continuous source 2-D example with a concentration threshold limit state function is used to evaluate the influence of the parameters in the location of interest on the reliability solution.

• Fire Science and Engineering
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• v.25 no.6
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• pp.58-63
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• 2011

This study is intended to present a computational thermal model for the combustibles in a residential building. As the Performance Based Design is more popular, fire-intensity and fire-load have turned out to be very important factors for building design and can be predicted through some computational work. To predict and estimate the thermal properties of the residential combustible fire, we made some numerical models of combustibles in a residential building. In a bid to validate the estimate values, computational analysis results from numerical models were compared with real fire tests. For computational analysis, the Fire Dynamics Simulator was used with Large Eddy Simulation model for turbulence. Consequently, each heat release rate and total heat release curves were successfully estimated.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.269-272
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• 2008

Blast load, an impulsive load with extremely short time duration with very high pressure, is effected by ground and air condition, weight of charge, shape and location of structure. In this study, a blast dynamic analysis for the air-structural integrated model considering dynamic properties of materials and simulation of complex blast wave propagation by Arbitrary Lagrangian- Eulerian technique is suggested to perform an accurate blast analysis of concrete structures. For the verification of the proposed blast analysis method, which is the air-structure integrated model using ALE technique, the comparison of analysis and experimental results is performed. The verification confirms that the simulation of realistic behavior of RC wall structures is possible using ALE method. Also, the example cases which have been analyzed using this method show that the estimation to the structural failure criterion for blast load failure can be represented by energy absorbtion procedure.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.2
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• pp.97-105
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• 1996

In this paper, an adaptive model predictive controller for nodinear processes using fuzzy model is proposed. Adaptive structure is implemented by recursive fuzzy modeling. The model and control law can be obtained the same as GPC, because the consequent parts of the fuzzy model comprise linear equations of input and output variables. The proposed Adaptive fuzzy model predictive controller (AFMPC) controls nonlinear process well due to the intrinsic nonlinearity of the fuzzy model. When AFMPC's output is variation in the process control input, it maintains zero steady-state offset for a constant reference input and has superior performance. The properties and performance of the proposed control scheme were examined with nonlinear plant by simulation.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.54.1-54.1
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• 2013

이 연구는 질량이 낮은 별탄생 지역에서 '에피소딕 질량수축 이론'을 관측과 수치모델로 테스트하였다. 스피쳐 우주망원경을 비롯한 여러 망원경으로 별 탄생 지역을 관측한 결과, 어린 별의 광도는 0.01 태양광도에 불과한 매우 낮은 값에서부터 높은 값까지 넓은 영역에 걸쳐 분포한다는 것이 알려졌다. 이 관측 결과는 70년대부터 있어 온 소위 표준 별탄생 모델의 예측과는 다른 결과이다. 관측과 표준 별탄생 모델의 차이를 풀기 위해서 에피소딕 질량수축 모델이 제안되었다. 테스트를 통하여 광도가 낮은 어린 별의 관측적 특성이 에피소딕 질량수축 모델로 한꺼번에 설명될 수 있음을 보였다. 우선, 카르마 전파 간섭계를 사용하여 전체 어린 별의 광도 분포에 해당하는 별 샘플을 선택하여 관측하였다. 표준 별탄생 모형은 중력수축이 진행됨에 따라 디스크 질량이 점진적으로 증가하지만 에피소딕 중력수축 모델은 디스크 질량과 별의 진화상태 사이에 특별한 연관관계가 없음을 예측한다. 여섯 개의 측정된 디스크 질량은 별의 진화상태와 상관없음을 보여주었다. 다음으로, 열아홉 개 어린 별의 이산화탄소 얼음을 적외선으로 분광 관측하고 분석하였다. 관측대상별 중 절반은 다른 분자와 섞이지 않은 순수한 이산화탄소 얼음이 존재한다는 증거를 보였고, 그 중 여섯 개는 순수 이산화탄소 얼음 존재의 강력한 증거인 두개의 픽이 나온 흡수선 형태를 보였다. 순수 이산화탄소 얼음 성분이 현재 광도가 낮은 별에서 존재한다는 것은 과거에 광도가 밝았던 시기, 즉 중력수축속도가 높았던 시기가 있었다는 것을 뒷받침한다. 화학진화모델에 에피소딕 중력수축 모델과, 일산화탄소 얼음이 이산화탄소 얼음으로 전환될 수 있다는 새로운 화학 네트워크를 포함한 모델로 광도가 낮은 어린 별에서의 순수 이산화탄소의 존재, 총 이산화탄소의 양, 그리고 관측된 일산화탄소 가스의 양을 모두 설명할 수 있었다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.217-225
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• 2017

This research represents comparison and validation of static aerodynamic results in different wind tunnel organizations and EFD-CFD results. KAFA conducted wind tunnel tests with Standard Dynamics Model(SDM) which is based on the NRC model, the same configuration of KARI; and then compared and analyzed similarities and differences of the data from KARI and NRC results for verifying the accuracy of wind tunnel tests. Also, We compared the result of CFD with that of wind tunnel tests and examined strakes effect in static characteristics which are attached on the forward fuselage of SDM for investigating the cause of some discrepancies. From this analysis, there are some discrepancies in Cm tendency between EFD-CFD and it did not show the big difference of aerodynamic characteristics by strake effects. Thus, we need to research additionally for analyzing the different cause of some discrepancies such as vortex structures by the rear strut or intake of SDM and regenerating grid resolution of CFD.