• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.117-119
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• 1995

입사파의 파장에 비교하여 그 대표 길이가 작은 소형 구조물에 작용하는 파력을 산정하는 경우에는 통상적으로 Morison식이 이용되고 있다. 원주나 판 등의 단순한 구조물에 관한 Morison식 중 유체력 계수(관성력 및 항력계수)에 관해서는 이미 많은 연구가 나와 있어 이들에 작용하는 파력을 고정도로 추정하는 것이 가능하다. 한편 이들 중에는 어초의 경우에서와 같이, 단순한 부재가 여러개로 조합되어 복잡한 구조물을 형성하고 있는 경우를 많이 볼 수 있다. (중략)

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.659-662
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• 2014

본 연구에서는 전산유체 해석프로그램인 EDISON_CFD를 이용하여 Clark-Y 에어포일의 공력특성 변화를 수치해석하고, 여러 가지 받음각의 변화를 통해 양력계수, 항력계수, 양항비 등을 도출하였다. 공력해석을 위한 조건으로 압축성 Navier-Stokes 방정식에 난류 유동조건을 적용하였다. 해석 결과는 에어포일 공력해석 툴로 널리 알려져 있는 XFOIL을 이용하여 비교 검토하였다.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.614-618
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• 2016

본 논문은 EDISON_CFD를 활용하여 화성에서 운용 가능한 풍력터빈에 대해 실험 및 개선 설계하였다. 본 연구에서는 화성의 중력 및 공기밀도 등 화성의 환경 데이터를 적용함으로써 풍력터빈의 형상을 새롭게 설계 하였다. 개선 설계는 기존의 풍력발전기 형상을 변형시키며 해석을 진행하였으며, 받음각과 형상에 따라 생성되는 토크를 확인하였다. 개선설계한 풍력터빈 모델은 단위 미터 당 약 8 W의 전력생산이 가능한 것을 확인하였다.

• Proceeding of EDISON Challenge
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• 2016.11a
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• pp.9-14
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• 2016

버드 스트라이크는 항공기 안전에 큰 위협을 주고 있다. 새를 막기 위하여 공항에서 여러 가지 방법들을 이용해 새를 쫓고 있지만 임시방편인 경우가 많거나 근본적인 방법은 아니다. 본 연구에서는 이러한 버드 스트라이크를 막기 위하여 새를 막는 장치를 엔진 흡입구에 장착하고, 이 흡입구가 엔진 흡입구의 성능에 어떠한 영향을 주는지 알아보려고 한다.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2845-2850
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• 2007

Flow-induced forces on two identical nearby circular cylinders immersed in the cross flow at Re =100 were numerically studied. We consider all possible arrangements of the two circular cylinders in terms of the distance between the two cylinders and the inclination angle with respect to the direction of the main flow. It turns out that significant changes in the characteristics of flow-induced forces are noticed depending on how the two circular cylinders are positioned, resulting in quantitative changes of force coefficients on both cylinders. Collecting all the numerical results obtained, we propose a contour diagram for drag coefficient and lift coefficient for each of the two cylinders. The perfect geometrical symmetry implied in the flow configuration allows one to use those diagrams to estimate flow-induced forces on two identical circular cylinders arbitrarily positioned in physical space with respect to the main flow direction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.117-125
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• 2006

In the present study the unsteady forces acting on the pitching foils such as a flat plate, NACA0010, NACA0020, NACA65-0910 and BTE have been measured by using a six-axis sensor in a circulating water tunnel at a low Reynolds number region. The unsteady characteristics of the dynamic drag and lift have been compared to the quasi-steady ones which are measured under the stationary condition. The pitching motion is available for keeping the lift higher after the separation occurs. Especially, the characteristics of the dynamic lift are quite different from the quasi-steady one at high pitching frequency regions. As the pitching frequency deceases, the amplitude of the dynamic lift becomes closer to the quasi-steady one. However, the phase remains different between the steady and unsteady conditions even at low pitching frequencies. On the other hand, the dynamic drag is governed strongly by the angle of attack.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.87-89
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• 2009

In the present paper, transition turbulence model is applied to the NACA64(3)618 and detailed flow features are studied. The turbulence model is sensitive to the boundary layer grid quality and y+ of the grid was limited to 1. The prediction of the transition region is dependent on the local flow condition. The pressure coefficient distribution of the transition turbulence model is compared with that of the fully turbulent mode and the drag distribution of the transition turbulence model was compared with that of the wind tunnel test.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.1
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• pp.155-161
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• 2001

Fundamental studies on the drag reduction of the circular cylinder having dimple were conducted by the measurement of the fluid force acting on the cylinder and by the flow visualization around the cylinder. The drag coefficients were changed by the shape and the geometrical arrangement of the dimple. The drag of the cylinder was reduced about 25% by the proper arrangement of the dimple. The flow field around the cylinder having dimple, which was the minimum drag, was visualized by the hydrogen bubble technique. In this case, the separation points were moved rearward and the wake region was small in comparison with that of the cylinder having no dimple.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.2
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• pp.44-52
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• 2001

A modeling program was developed in Part I which represents the 3-D geometry, produces bill of material, automatically draws drawings and produces input data for structural analysis of Very High-rise Steel Artificial Reefs(VEHSAR). Model tests were carried out to measure drag forces acted on VEHSAR in the Ocean Engineering Wide Tank, the University of Ulsan and structural analyses were made to simulate structural behaviors of VEHSAR. The integrated package system is suggested to design VEHSAR with different geometries.

• Journal of computational fluids engineering
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• v.7 no.3
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• pp.1-8
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• 2002

The counter jet flow which is injected against the free stream at stagnation region of blunt body for improvement of aerodynamic performance has been studied by using upwind Navier-Stokes method. The variations of drag force and upwind forward penetration depth due to changes in the stagnation thermodynamic properties of counter jet flow such as total pressure, Mach number, and total temperature have been studied. The results show that the changes in the stagnation pressure and Mach number have large effects on the wall pressure and drag force, but the total temperature does not affect the wall pressure and drag force.