• 한국산학기술학회논문지
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• 제3권4호
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• pp.251-256
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• 2002

폴리머용액의 특성확산시간은 낙구의 종말속도를 측정함으로써 결정할 수 있다. 확산시간은 폴리머 용액의 농도가 증가할수록 증가한다. 입자영상유속장치 (PIV)를 이용하여 구주위의 유동현상을 가시화 하였다. 2000 ppm의 경우 30 초 간격으로 떨어뜨렸을때의 속도가 0초( 처음)나 40초후, 50초후에 떨어뜨렸을때와 비교하여 가장 크게 나타났다. 뉴톤 유체에서는 낙구의 전방과 후방에서 구주위의 유동장이 동일하게 나타났다.

• 대한기계학회논문집
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• 제5권3호
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• pp.238-243
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• 1981

An empirical formula for the mass flow rate in natural convection flume above a spherical heated body which is submerged in a finite fluid contained in a tank was determined. The ratio of depth of submergence to diameter of the sphere for which the sphere sensed as infinite medium was found to be bigger than 7. A dimensionless heat transfer correlation for the natural convection from a sphere was determined for Gr.Prq etween 7x10$\^$7/ and 2x10$\^$8/ also.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.106-109
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• 2006

A large eddy simulation with explicit filters on unstructured mesh is presented. Two explicit filters are adopted for reducing the aliasing error of the nonlinear convective term and measuring the level of subgrid scale velocity fluctuation, respectively. The developed subgrid scale model is basically eddy viscosity model which depends on the explicitly filtered fields and needs no additional ad hoc wall treatment such as van Driest damping function. As a validation problem, the flows around a sphere at several Reynolds numbers, including laminar and turbulent regimes, are calculated and compared to experimental data and numerical results in the literature.