Flow structures and drag characteristics of a colony-type emergent roughness model mounted on a flat plate in uniform flow
スポンサーリンク
概要
- 論文の詳細を見る
The characteristics of flow structures around a colony-type emergent roughness model, hereafter called 'colony model'. mounted on a flat plate in uniform flow and the drag coefficient C-dc for the colony model are investigated by flow visualization, spectral analysis, velocity measurement and drag force measurement. Two types of colony models. each comprising seven equally spaced cylinders with grid or staggered arrangement are mounted on a water flume bed. The flow structure around the colony model changes depending on LID and G/D (L: space between neighboring cylinders, D: diameter of a cylinder, G: space between cylinders in the cross-stream direction). Two types of flow structures. a large-scale Karman vortex street (LKV) behind the colony models and a primitive Karman vortex street (PKV) behind the individual cylinders, are generated. LKV is formed along the shear layer for G/D < 0.4. When G/D > 1.8 PKV behind each cylinder is stably formed because of the decrease in difference between the velocity through the colony model and that of the detour flow. The velocity through the colony model, which plays a key role for the phenomenon change, strongly increases with G/D at first and then gradually. The tendency of the velocity curve changes around G/D = 1.8 for each arrangement. It almost coincides with the initiation of the formation of PKV. On the other hand, Cdc for the colony model increases in the range of 0.08 < G/D < 0.75 (0.25 < LID < 1) and 0 < G/D < I (I < LID < 3) for the grid and staggered arrangements, respectively. The changing point of the tendency in the C-dc, curve is located in the middle of the transition zone for the two vortex(0.4 < G/D < 1.8). Moreover, the C-dc value for the colony model is nearly constant, independent of the two arrangements, when G/D > 1.8. (c) 2007 The Japan Society of Fluid Mechanics and Elsevier B.V. All rights reserved.
- 2007-09-10
論文 | ランダム
- 先天性神経芽腫の1例
- ガウディの射影-12完-信仰--表現を総合して構造と形態の一致を超越
- ガウディの射影-9-量感--強調することで自然を感得させる効果
- ガウディの射影-8-表面--触覚的効果が生む大地からの飛躍
- ガウディの射影-10-芸術--調和がもたらす究極の建築世界