| Budget Amount *help |
¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2012: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2011: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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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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