• EDISON SW 활용 경진대회 논문집
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• 제1회(2012년)
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• pp.121-124
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• 2012

비정상 유동 해석을 수행하는데 있어서 비정상 Navier-Stokes 방정식을 적용한 결과와 정상 N-S 지배 방정식을 적용한 결과의 차이를 비교하려한다. 적용하고자 하는 비정상 유동은 대칭형 에어포일 NACA0012 에어포일 주위 유동으로 정하였으며, 이 때 에어포일 시위(chord) 길이와 자유류(free stream) 속도 기준으로 Re=100,000에 해당한다. 계산결과 비정상 지배 방정식을 적용한 경우 비정상 유동박리(flow separation)를 모사 할 수 있었으며, 평균 양력계수($C_L$)와 항력계수($C_D$)는 실험치와 비교적 잘 일치하였다. 하지만 정상 N-S 방정식을 적용했을 경우 비정상 유동을 모사하기 어려웠으며 평균양력, 항력계수도 실험치와 차이를 보였다. 이러한 결과는 비정상 유동 해석시 시간에 따라 변화하는 유동의 특성을 고려해 비정상 N-S 지배 방정식을 적용해야한다는 사실을 보이고 있다.

• 풍력에너지저널
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• 제5권1호
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• pp.22-32
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• 2014

The structural design of a wind turbine must show the verification of the structural integrity of all load-carrying components. Also, design load calculations shall be performed using appropriate and accurate methods. In this study, advanced numerical approach for the calculation of design loads based on unsteady computational fluid dynamics (CFD) is presented considering extreme design load conditions such as the extreme coherent gust (ECG) and the 50 year extreme operating gust (EOG). Unsteady aerodynamic loads are calculated based on Reynolds average Navier-Stokes (RANS) equations with shear-stress transport k-ω(SST k-ω) turbulent model. A full three-dimensional 5 MW offshore wind-turbine model with rotating blades, hub, nacelle, and tower configuration is practically considered and its aerodynamic interference effect among blades, nacelle, and tower is also accurately considered herein. Calculated blade loads based on unsteady CFD method with respect to blade azimuth angle are compared with those by NREL FAST code and physically investigated in detail.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.171-177
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• 2011

In this paper, a square simply supported panel flutter have been considered at high supersonic flow by using coupled fluid-structure (FSI) analysis that based on time domain method. The Reynolds-Average Navier Stokes (RANS) equation with Spalart-Allmaras turbulent model were applied for unsteady flow problems of panel flutter. A fully implicit time marching schemed based on the Newmark direct integration method is used for calculating the coupled aeroelastic governing equations of it. In addition, the SOL 145 solver of MSC.NASTRAN was used to investigate flutter velocity based on PK-method of Piston theory. Our numerical results indicated that there is a good agreement result between Piston Theory in MSC.NASTRAN and coupled fluid-structure analysis.