Evaluation of Hydrodynamic Forces with Nonlinear Wave Equations for a Compressible Fluid

用非线性波动方程评估可压缩流体的水动力

• 批准号: 07650591
• 负责人: IZUMIYA Takashi
• 金额: $ 1.15万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650591/
• 关键词: hydrodynamic force; impact pressure; nonlinear wave; compressible fluid; bubbly fluid; 衝撃波力; ヘルムホルツ方程式

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.

为了研究运动的非线性对流体动力的影响，建立了可压缩流体的非线性波动方程。在简谐运动的情况下，用摄动法求解非线性方程。根据一阶解计算了非线性项的大小，并与线性项的大小进行了比较。结果表明，波浪力的非线性在自由面附近较为显著，而在其它区域则很小。当垂直壁前水体中含有气泡时，冲击压力振荡得到阻尼。为了模拟这种现象，使用了液体和气体气泡混合物的非线性运动方程。该方程包括弥散和耗散以及非线性的影响，类似于水波的Boussinesq方程，并进行了数值求解。数值结果表明，空气含量越大，冲击压力的大小越小。

项目成果

泉宮尊司,田辺剛: "鉛直加速度を考慮した地震時動水圧の評価" 土木学会海岸工学論文集. 42. 821-825 (1995)

Takashi Izumiya、Tsuyoshi Tanabe：“考虑垂直加速度的地震期间的水压评估”日本土木工程师学会会议记录，海岸工程学报 42. 821-825 (1995)。

泉宮 尊司・阿部宏之: "海水の圧縮性と鉛直共鳴による海面変動の増幅メカニズム" 土木学会海岸工学論文集. 第43巻. 421-425 (1996)

Takashi Izumiya 和 Hiroyuki Abe：“由于海水压缩性和垂直共振导致的海平面变化的放大机制”，日本土木工程学会论文集，海岸工程学，第 43 卷，421-425（1996 年）

泉宮尊司,田辺剛: "地震時動水圧に与える非線形性および重力項の影響" 土木学会海岸工学論文集. 42. 816-820 (1995)

Takashi Izumiya、Tsuyoshi Tanabe：“地震期间非线性和重力项对水压的影响”日本土木工程师学会会议记录，海岸工程学报 42. 816-820 (1995)。

泉宮 尊司・田辺 剛: "地震時動水圧に与える非線形性および重力項の影響" 土木学会海岸工学論文集. 第42巻. 816-820 (1995)

Takashi Izumiya 和 Tsuyoshi Tanabe：“地震期间非线性和重力项对水压的影响”《海岸工程学报》，日本土木工程师学会，第 42 卷，816-820 (1995)

泉宮尊司・田辺剛: "地震時動水圧に与える非線形性および重力項の影響" 土木学会海岸工学論文集. 第42巻. 816-820 (1995)

Takashi Izumiya 和 Tsuyoshi Tanabe：“地震期间非线性和重力项对水压的影响”《海岸工程学报》，日本土木工程师学会，第 42 卷，816-820 (1995)