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윤현식,양선희,이유경,Yoon, H.S.,Yang, S.H.,Lee, Y.K. 한국전자통신연구원 2001 전자통신동향분석 Vol.16 No.1
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가진 주파수에 따른 이차원 사각탱크 내부의 슬로싱에 관한 수치적 연구
정재환(J.H. Jung),이창열(C.Y. Lee),윤현식(H.S. Yoon),김효주(H.J. Kim) 한국전산유체공학회 2015 한국전산유체공학회지 Vol.20 No.1
The present study investigates the sloshing phenomena in a two-dimensional rectangular tank at a low filling level by using a level set method based on finite volume method. The code validations are performed by comparing between the present results and previous numerical and experimental results, which gives a good agreement. Various excitation frequencies and excitation amplitude of the 30% filling height tank have been considered in order to observe the dependence of the sloshing behavior on the excitation frequency and amplitude. Regardless of excitation amplitude, the maximum value of wall pressure occurs when the excitation frequency reaches the natural frequency. The time sequence of free surface and corresponding streamlines for excitation frequencies have been presented to analysis the variation of wall pressure according to time, which contributes to explain the double peaks in the time variation of wall pressure.
아임계 레이놀즈 수에서 트위스트 실린더 주위 유동의 LES 해석
정재환(J.H. Jung),윤현식(H.S. Yoon) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
The flow around a twisted cylinder at a subcritical Reynolds number (Re) of 3000 is investigated using large eddy simulation (LES). The instantaneous wake structures of the twisted cylinder is compared with those of a circular and a wavy cylinder at the same Re. The shear layer of the twisted cylinder covering the recirculation region is more elongated than those of the circular and the wavy cylinder. Successively, vortex shedding of the twisted cylinder is considerably suppressed, compared with those of the circular and the wavy cylinder. Consequently, the mean drag coefficient and the fluctuating lift of the twisted cylinder are less than those of the circular and the wavy cylinder.
NUMERICAL STUDY ON FLOW AROUND LOW ASPECT RATIO WING FOR THE WAVY LEADING EDGE
M.J. Kim(김미정),H.S. Yoon(윤현식),H.H. Chun(전호환) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5
The present study numerically investigates the effect of the wavy leading edge on hydrodynamic characteristics for the flow of rectangular wings with the low aspect ratio of 1.5. two different wave lengths of S/4 and S/8 at fixed wavy amplitude of 0.05C have been considered, where S and C are the span length and the mean chord length of the wing, respectively. Numerical simulations are performed at a wide range of the angle of attack (0° ≤ α ≤ 40° )at one Reynolds number of 10<SUP>6</SUP>. In the pre-stall region, the wavy wings reveal the considerable loss of the lift, compared to the smooth wing. In the post-stall, the lift coefficients of the smooth wing and the wavy wings are not much different.