| Project/Area Number |
07650591
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | Niigata University |
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Principal Investigator |
IZUMIYA Takashi Niigata Univ.Dept.of Civil Eng.Associate Professor, 工学部, 助教授 (60151429)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | hydrodynamic force / impact pressure / nonlinear wave / compressible fluid / bubbly fluid / 衝撃波力 / ヘルムホルツ方程式 |
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| Research Abstract |
A nonlinear wave equation for a compressible fluid was derived to investigate effects of nonlinearlity of a motion on hydrodynamic forces. The nonlinear equation was solved by a perturbation method in case of harmonic motion. The magnitude of nonlinear term was evaluated in term of first order solution and compared with those of linear term. It was found that the nonlinearity of hydrodynamic forces was significant in the vicinity of a free surface, while it is negligibly small in other region.
Lavoratory experiments were conducted to investigate characteristics of wave impact pressure on a vertical wall. The impact pressure oscillation was damped when air bubbles were contained in a water body in front of a vertical wall. To simulate this phenomenon, nonlinear equations of motion for mixtures of liquid and gas bubbles were used. The equations includes the effects of dispersion and dissipation as well as nonlinearity, similar to the Boussinesq Equations for water waves, and were solved numerically. The numerical results indicated that the larger the air content, the lower the magnitude of the impact pressure.
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