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RANS 모델링을 이용한 Hump 형상의 박리 유동에 대한 연구
이재훈(J. Lee),배중헌(J.H. Bae),정경진(K.J. Jung) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.1
In this paper, separated flow characteristics is studied using the RANS(Reynold-averaged Navier-Stokes) modeling. The analysis is performed for the NASAs hump configuration which is the combination of a flat plate and a hump. This configuration was used in NASAs flow control workshop and it was one of validation cases for RANS and LES simulations. The separation occurs at the 65% of model length where a slot is positioned for the flow control. No flow control case and steady suction case are studied using RANS modeling. The Spalart-Allmaras model and the SST(Shear Stress Transport) model are applied and their accuracy are compared. To correlate CFD analysis with experimental data, the optimal boundary condition was investigated and the effect of a cavity around the slot is studied for the no flow case.
이재훈(J.H. Lee),이수강(S.G. Lee),이병주(B.J. Yi),이석희(S.H. Lee),이정헌(J.H. Lee),김희국(W.K. Kim) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월
In this study, a spatial 3-dof haptic mechanism is implemented. The implemented mechanism does not employ the gear transmissions as velocity reducers for all three joints but uses wire-based transmissions, thereby it is able to minimize the frictions significantly. Also, by employing the structure of the four-bar mechanism to drive third joint from close to the base, the mechanism is able to minimize the inertia effect from the third actuator very effectively. Its kinematic analysis such as position and velocity analyses are performed first. Then, its operating software development, hardware implementation, and the related interfaces between a PC and the implemented Haptic device are completed. To evaluate its potential and its performance as a haptic device, a experiment generating a virtual constraint in a operational task space is conducted and preliminary results are discussed.