• 대한기계학회논문집
• /
• 제3권4호
• /
• pp.164-172
• /
• 1979

Experimental and numerical results concerning the flat punch indentation to semi-infinite body with partially constrained free surface are presented The distributions of slip line directions are predicted by Moire fringe analysis using Vinckier's method. A mumerical study is made of the same problem by finite element method and the results are compared with the experimental results. It is shown that the contour feature of possible slip line field is similar to that of well-known Prandtl indentation sloution.

• 태양에너지
• /
• 제2권1호
• /
• pp.33-48
• /
• 1982

A planetary boundary layer model has been modified to study the feasibility of siting the wind energy conversion systems over Jejudo island. Our objective is to demonstrate a numerical model that is simple enough to be economical in terms of computational cost and contains most of the mesoscale processes occurring in the planetary boundary layer at the same time. Simulated fields of atmospheric parameters are compared favorably with available climatological data and interpreted in terms of physical phenomena occurring.

• KSTLE International Journal
• /
• 제2권1호
• /
• pp.59-64
• /
• 2001

A new bearing concept, the wave journal bearing, has been developed to improve the static and dynamic performance of a hydrodynamic journal bearing. This concept features a wave in bearing surface. Not only straight but also twisted wave journal bearings are investigated numerically. The performances of straight and twisted bearings are compared to a plain journal bearing over a wide range of eccentricity. The bearing load and stability characteristics are dependent on the geometric parameters such as the number of waves, the amplitude and the starting point of the wave relative to the applied load direction. The bearing performance is analyzed for various configurations and for both cases of smooth and wave member notation. The wave journal bearing, especially for the twisted one, offers better stability than the plain journal bearing under all eccentricity ratios and load orientation.

• 한국해양공학회지
• /
• 제10권1호
• /
• pp.81-91
• /
• 1996

Numerical study is carried out to make clear the wavemaking phenomena for a planning flat plate. Through the mumerical computations, some schematic wave patterns are compared with experimental results, for example, such as the bow divergent waves, triangle waves, stern divergent saves, stern cross waves. The characteristic distance of waves is found to be more inconsistent as the incidence angle increases. The comparison was mode between computations and experiments for incidence angles of 5, 10 and 15 degrees. However, a numerical difficulty is found around and behined the trailing edges for more than 20 degree.

• Korean Journal of Hydrosciences
• /
• 제3권
• /
• pp.61-79
• /
• 1992

In oder to predict the dispersion of a thermal discharge with strong turbulent and buoyant effects, the development of a numerical model using turbulence model and its application are significantly increased. In this study, a three-dimensional steady-state model for the surface discharge heated water into quiescent water body is developed. For the model closure of turbulent terms the four-equation turbulence model is used. For economic mumerical simulation, the elliptic governing equations are transformed to the partially parabolic equations. In general, the simulated results by the present model agree well with the experimental results by Pande and Rajratnam (1977). The model characteristics are presented in comparison with the predicted results from the two-eqauation turbulence model by McGuirk and Rodi (1979).

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.523-526
• /
• 2000

This paper performs the motion analysis for a disk cam and a follower mechanism using a circular arc method, a coordinate transformation method and an instant velocity method in order to find a contact point between the cam and the follower. Based on the proposed method, the displacement and the velocity are calculated by using the geometric relationships of the cam mechanism. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

• 한국산학기술학회논문지
• /
• 제20권1호
• /
• pp.456-463
• /
• 2019

가축 사육 시설 내부의 온도, 습도 등과 같은 미기상 요소는 환기, 냉방, 난방, 단열, 가축의 현열 및 잠열과 같은 에너지 발생 등 다양한 요소의 복합적인 영향을 받는다. 본 연구에서는 위와 같은 다양한 변수에 따른 시설 내부의 에너지 흐름 및 기작을 구현하기 위하여 BES 수치해석 기법을 활용하였다. BES 수치해석 모델 및 THI 지수 개념을 이용하여 국내 주요 지역별 가금 사육 시설 내부의 고온 스트레스 발생 정도를 정량적으로 산정하고자 하였다. 또한, 최근 동물복지 사육이슈에 따라, 현행 기준 및 동물복지를 고려한 사육 밀도 적용 시, 시설 내부의 THI 지수를 비교 분석하였으며, 그 결과, 환절기 시기의 경우 사육밀도 감소에 따른 유의한 고온 스트레스 감소 효과가 도출되었으나(p<0.05), 하절기의 경우 큰 차이를 보이지 않아(p>0.05) 지역별 적정 냉방시설의 설비 마련이 시급한 것으로 나타났다. 전라북도 익산시의 경우, 사육밀도 감소에 따라 고온 스트레스 발생 시간 기준, 총 252시간의 이득이 있는 것으로 산출되었다.