• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.176-180
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• 2001

For windshield defrosting, flow analysis of inner room(vehicle) and heat conduction on the windshield surface are undertaken. Simulation for defrosting enthalpy method is usedand verification of heat and fluid flow analysis for room is done in cavity flow. The defrosting process is three dimensional phenomena and phase is changing. The result of defrosting analysis are well presenting the phase change and these results offer basic design data for defrosting phenomena.

• 지구물리
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• 제4권4호
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• pp.231-238
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• 2001

In this paper, an efficient LP method ofr discrete harmonic spectra is proposed and discussed. A new efficient LP method is a combination of recursive and frequency selective LP. While the recursive LP provides better spectral matching in spectral hills, frequency selective LP eliminates numerical instability and improves spectral matching when the harmonics are confined in the low frequncy region. The proposed LP method is applied to the HILN coder. Simulation results using a verification model(VM) software for real audio signals show a definite trend of significant improvement.

• 한국전자파학회논문지
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• 제7권4호
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• pp.320-327
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• 1996

This paper presents that the lossy or amplification property of the Finite Difference-Time Domain(FD-TD) method based on the leap-frog scheme is theoretically verified by using a plane wave analysis. The basic algorithm of the FD-TD method is introduced in order to help understanding the analysis procedure. Since our analysis is formulated by the Von Neumann's approach, the stability inequality is also produced as an another outcome.

• 공학논문집
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• 제5권1호
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• pp.37-44
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• 2004

n this paper, an efficient LP method for discrete harmonic spectra is proposed and discussed. A new efficient LP method is a combination of recursive and frequency selective LP. While the recursive LP provides better spectral matching in spectral hill, frequency selective LP eliminates numerical instability and improves spectral matching when the harmonics are confined in the low frequency region. The proposed LP method is applied to the HILN coder. Simulation results using a verification model(VM) software for real audio signals show a definite trend of significant improvement.

• 대한조선학회논문집
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• 제56권3호
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• pp.231-241
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• 2019

In this study, a simplified analysis method was developed to evaluate the fatigue damage of an ice-going ship under broken ice condition. The global ice load, which is essentially calculated at the design stage of the Arctic vessel, and the hull form information were used to estimate the local ice load acting on the outer-shell of the ship. The local ice load was applied to the finite element analysis model, and the Weibull parameters for the target fatigue point were derived. Finally, fatigue damage was evaluated by applying the S-N curve and the Palmgren-Miner rule. For the verification of the proposed method, numerical analyses using direct approach were performed for the same conditions. A numerical model that implements the interaction between ice and structure was introduced to verify the local ice load and the stress calculated from the proposed method. Finally, the fatigue analyses of the Baltic Sea for actual ice conditions were performed, and the results of the proposed method, the method using numerical analysis, and the LR method were compared.

• 한국해양공학회지
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• 제22권1호
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• pp.70-74
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• 2008

It is important to reduce the vibration and noise of submarines and ships. For the purpose of noise reduction, various researches are actively being conducted on the employment of complex structures. However, in the case of numerical analysis for complex structures with damping materials, substantial errors can be generated by the absence of an exact damping model. Thus experimental model analysis is necessary for the verification of a numerical analysis for complex structures. In this research, vibration experiments are conducted in order to ascertain the vibration properties of cantilever beam attached damping materials. First, an initial value is obtained by using a direct linear method. Next, based on this initial value, the exact modal parameters of the cantilever beam are obtained by using the Newton-Raphson method.

• 대한조선학회논문집
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• 제47권2호
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• pp.188-195
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• 2010

Green water load is an important parameter to be considered in designing a modern ship or offshore structures like FPSO and FSRU. In this research, a numerical simulation method for green water phenomenon is introduced. The Navier-Stokes equations and the continuity equation are used as governing equations. The equations are calculated using Finite Difference Method(FDM) in rectangular staggered grid system. To increase the numerical accuracy near the body, the Cartesian cut cell method is employed. The nonlinear free-surface during green water incident is defined by Marker-density method. The green waters on a box in regular waves are simulated. The simulation results are compared with other experimental and computational results for verification. To check the applicability to moving ship, the green water of the ship which is towed by uniform force in regular wave, is simulated. The ship is set free to heave and to surge.

• 방사성폐기물학회지
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• 제10권4호
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• pp.237-246
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• 2012

본 연구에서는 콜로이드와 핵종의 복합이동에 관한 수치모델을 개발하였다. 콜로이드와 핵종의 반응-이동 지배방정식을 풀기 위하여 Operator Splitting Method 중 Strang의 분리 SNI 방식을 수치해석 방법으로 채택하였고 이는 MATLAB을 이용하여 코드화 되었다. 개발된 수치모델은 용질의 이동 및 분산만을 고려한 해석해를 통한 검증과정에서 피어슨 상관계수의 제곱값($r^2$)이 0.99 이상으로 나타나 모델의 정확성이 입증되었다.

• 한국지반신소재학회논문집
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• 제5권2호
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• pp.9-15
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• 2006

흙막이벽 굴착배면지반의 변형거동을 해석을 하기 위하여 강제변위법을 이용한 수치해석 프로그램을 개발하였다. 굴착지반의 구성모델은 Drucker Prager의 비선형 탄소성구성방정식을 적용하였으며, 리턴매핑법으로 탄소성해를 구하였다. 수치해석 프로그램의 타당성을 검증하기 위하여 수치해석으로부터 얻은 굴착배면지반의 수평변위와 현장계측결과를 비교하였다. 검토결과 수치해석 프로그램의 정확도는 상당히 높은 것으로 나타났다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.241-244
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• 2009

This paper deals with a usefulness verification of stretch forming process using flexible die. The stretch forming method is widely used in aircraft and high-speed train industries for manufacturing of skin structure, which is made of sheet metal. A great number of solid dies are originally used and developed for specific shapes with respect to different curvature radii of the skin structures. Accordingly, flexible stretch forming process is proposed in this study. It replaces the conventional solid dies with a set of height adjustable discrete punches. A usefulness of the flexible die is verified through extensive numerical simulations of the stretch forming process for simply curved sheet plate. The elastic recovery is considered and formability evaluations are conducted through a comparison of symmetry plane configurations.