0117 矩形ダクト流における局在乱れ構造(OS1 噴流,後流および剥離流れ現象の探求と技術革新,オーガナイズドセッション)

DOI Web Site

書誌事項

タイトル別名
  • 0117 Localized turbulence structures in rectangular-duct flow

抄録

Subcritical transition to turbulence in wall-bounded shear flow is known to be characterized in terms of turbulent patches bounded by laminar regions. In this study spatially localized turbulence structures are investigated in rectangular-duct flow of cross-sectional aspect ratios A_S = 1 - 9 at marginal Reynolds number Ret. The lowest Reynolds number Ret for transient turbulence is determined to demonstrate its dependence on the aspect ratio As. It is found that Ret monotonically decreases from Ret = 730 for As = 1 with increasing As, and for As = 5 it nearly attains to a minimal value Re_T ≒ 670 which is consistent with the Reynolds number for the appearance of a turbulent puff in a plane channel (As = ∞). Streamwise-localized (turbulent puff), or streamwise- and spanwiselocalized (turbulent spot) turbulence are observed at the Reynolds numbers Re = Re_T for distinct As. The localized turbulence exhibits structural 'transition' between a turbulent puff and a turbulent spot around As = 4.

収録刊行物

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ