| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2015: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2014: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2013: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
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| Outline of Final Research Achievements |
We studied process and condition of transition to a turbulent puff that is local turbulence observed in a pipe flow as catastrophic flow transition to turbulence. (1) A fine pipe flow facility with 8 m in the pipe length and 32 mm in the inner diameter of pipe that realizes laminar flow for more than 25,000 of Reynolds number without perturbation was constructed. (2) Novel visualization technique was established to extract vortical structure in a puff effectively. Through experiments, (3) complex edge of turbulence that was found by our previous study was represented in this system and physics embedded in the complex edge was elucidated, and further, (4) influence of adding microbubbles into pipe flows were investigated statistically: turbulent puffs were stabilized by adding bubbles.
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