| Project/Area Number |
18K03942
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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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| Review Section |
Basic Section 19010:Fluid engineering-related
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| Research Institution | University of Tsukuba |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | ソリトン / 衝撃波 / キャビテーション / 気泡 / 圧力波 / 非線形波動 / 混相流 / 気泡流 / 音響ソリトン / 弱非線形 / 非線形効果 / 分散効果 / 散逸効果 / 非線形波動方程式 / 非線形音響学 / 多分散性 / 安定性解析 / 二流体モデル / 超音波造影剤 / 粘弾性体 / 超音波 / 分散性波動 / 気泡力学 / 抗力 / 並進 / 多分散 / 実効ポリトロープ |
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| Outline of Final Research Achievements |
In order to supress a damege of water pipe, we aimed a transition of shock waves in water into acoustic solitons. By utilizing a weak nonlinear effect of cavitation, the dispersion effect of waves caused by bubble oscillations appears, and when the nonlinear and dispersion effects are balanced, a soliton can be formed. On the other hand, when the nonlinear effect is balanced by the dissipation effect, a shock wave is formed. Therefore, quantitative evaluation of the three effects (i.e., nonlinear, dissipation, and dispersion effects) can lead to realization of the above idea. Focusing on the nonlinear wave equation as a mathematical model expressed as a linear combination f three terms representing these three effects, we developed various nonlinear wave equations including a fast propagation mode, and through quantitative evaluation of the three effects, we predicted the evolving waveform of pressure waves.
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| Academic Significance and Societal Importance of the Research Achievements |
【学術的意義】非線形波動方程式の導出により得られた数理物理・応用数学的意義、非線形・散逸・分散の評価と発展波形予測（衝撃波・ソリトン等）による流体力学的意義、気泡流の平均化モデル方程式の構築による流体工学的意義などが挙げられ、多岐にわたる学術的知見を得られた。
【社会的意義】われわれの生活に欠かせない水管に対して、その損傷をソリトンにより回避しながらも、衝撃波の活用により洗浄を行うという新たな技術を提案し、受賞等によって一定の評価を受けた。今後は、損傷回避と洗浄を両立可能なハイブリッド新技術の開発と実用化に向けた研究も展開させる。
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