2013 Fiscal Year Final Research Report
Study on drag reduction mechanism with emphasis on non-affinity in polymer chain coil-stretch transition
| Project/Area Number |
23560188
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
HORIUTI Kiyosi 東京工業大学, 理工学研究科, 准教授 (10173626)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 抵抗低減 / 高分子添加溶液 / 界面活性剤 / 粘弾性流体 / Brownian dynamics / Elastic dumbbell model / 反変・共変ベクトル / エネルギーカスケード |
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| Research Abstract |
We carried out numerical study to reveal the mechanism of drag reduction (DR) in polymer-diluted flows. The polymer chains are modeled as elastic dumbbells. We elucidated the effect of non-affinity in the motion of dumbbells on DR, where their motions do not precisely correspond to macroscopically-imposed deformation. The DNS for the solvent is coupled to the mesoscopic description of dumbbells using BDS in forced homogeneous isotropic turbulence. Compared with the complete affine case (a=0.0), more drastic DR is achieved when non-affinity is maximum (a=1.0). When a=0.0, the dumbbell connector vector is convected as contravariant vector representing material line element and elasticity is caused on the tubular structures. When a=1.0, the connector is convected as covariant vector representing material surface element, and directs outward perpendicularly on the planar structures and exert an extra tension on vortex sheet, which leads to attenuation of energy cascade, causing larger DR.
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