November 02 (Thursday)
전산유체(IV)/난류
Oral,
제5발표장(203호),
08:40~09:40
  • Chair :
  •  이연원(부경대)
Th05A-2
08:40~09:40
역압력 구배 난류 경계층 유동 내 대형 구조가 표면 저항에 미치는 진폭 변조 영향

윤민, 황진율, 성형진(KAIST)
Direct numerical simulation of a turbulent boundary layer subjected to an adverse pressure gradient (β = 1.45) at Re_τ = 834 is performed to explore amplitude modulation influences of large scales on the skin friction. The correlations vω_z and -wω_y representing the advective vorticity transport and the vortex stretching, respectively, are directly related to the skin friction coefficient (C_f), and they affect the decrease and increase in C_f, respectively. Large-scale streamwise velocity fluctuations (u_L) are extracted by employing a long-wavelength-pass filter with a cut-off wavelength of λ_z^+ = 400 The correlations vω_z and -wω_y are conditionally averaged with respect to u_L. The enhanced large scales strongly modulate the vortical motions related to the skin friction. In particular, the negative-u_L events augment the contribution of vω_z to the skin friction, and the contribution of -wω_y is enhanced by the positive-u_L events
Keywords : direct numerical simulation(직접수치모사), turbulent boundary layer(난류 경계층), adverse pressure gradient(역압력 구배)
Paper : Th05A-2.pdf

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