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벽면 전단 유동의 공력 소음 해석을 위한 유동-음향 분리 기법
서정희(J. H. Seo),문영준(Young J. Moon) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4
Aeolian tone generation from a two dimensional circular cylinder is numerically investigated via<br/> direct numerical simulation and hydrodynamic-acoustic splitting method. All governing equation are<br/> spatially discretized with the sixth-order compact scheme and fourth-order Runge-Kutta method to avoid<br/> excessive numerical dissipations and dispersions of acoustic quantities. Comparisons of two results show<br/> that the previous splitting method can not accurately predict the aeroacoustic noise of wall bounded<br/> shear flow. In this study, a perturbation viscous term and a new energy equation have been developed.<br/> This modified splitting method accurately predicts aeroacoustic noise from wall-bounded shear flow. The<br/> present results agree very well with the direct numerical simulation solution.
공기부상 전동 운행체의 지면효과를 받는 3차원 날개에 대한 공력해석 연구
오현준(H. J. Oh),서정희(J. H. Seo),문영준(Y. J. Moon),조진수(J. S. Cho),윤용현(Y. H. Yoon) 한국전산유체공학회 2004 한국전산유체공학회 학술대회논문집 Vol.2004 No.-
Aerodynamic characteristics of three-dimensional wings in ground effect for Aero-levitation Electric Vehicle(AEV) are numerically investigated for various ground clearances and wing spans at the Reynolds number of 2×10^6 Numerical results show that a sizeable three-dimensional flow separation occurs with formation of an arch vortex at the junction of main and vertical wings, and that this is conjectured a primary cause for the high lift-to-drag(L/D) reduction rate of the main wing, when the wing span is decreased. Improvements on L/D ratios of the wings with small spans are pursued by breaking the coherence of superimposed adverse pressure gradients at the wing junction.