| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2013: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2012: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Outline of Final Research Achievements |
An experimental study has been performed in order to investigate the relationship between the extensional viscosity of polymers and turbulent drag reduction (DR). Self-standing flowing soap film was used to obtain Two-dimensional grid turbulence which is mostly dominated by extensional flow. Polyethyleneoxide, as a flexible polymer, and hydroxypropyl cellulose, as a rigid rod-like polymer were added to the flow. The effects of these polymers were visualized by the interference pattern of flowing soap films. The vortex deformation by adding polymers was analyzed by Fourier transformation and wavelet transformation. The scaling exponents of the power spectrum of interference patterns indicate that the mechanism of DR due to the extensional viscosity is anisotropic. A wavelet analysis reveals the high and low fluctuations of the polymer added flow. Results from wavelet analysis indicate disappearing of original vortices, and appearing of new structures in low frequency in 2D flow.
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