著者

今北 明彦 安田 章宏

出版者

社団法人 日本船舶海洋工学会

雑誌

日本船舶海洋工学会論文集 (ISSN:18803717)

巻号頁・発行日

vol.6, pp.379-386, 2007 (Released:2008-03-18)

参考文献数

10

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This paper describes numerical simulations and experimental results of dynamic response of a cylindrical floating structure subjected to an underwater explosion. An explosion was generated by wire explosion method under the center of bottom plate. Responses of the cylinder were recorded in the experiments with three different offset conditions. Nonlinear explicit finite element method and finite volume method were used for the structural analysis and the fluid analysis respectively. Compressibility of fluid and fluid structure interaction were taken into account in the numerical simulation. Explosion bubble shape was observed with a high speed camera and were compared with the numerical simulation results. Experimental results of time histories of bottom surface pressures and displacement of the bottom plate were also compared with the numerical simulation results. Numerical simulation results regarding to dynamic response of the cylinder corresponded well with experimental results. Discussions are given to boundary effects on behavior of explosion bubble and offset distance effects on response of the cylinder.

著者

神保 佳典 高比良 裕之 小林 一道 安田 章宏

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.76, no.762, pp.219-229, 2010-02-25 (Released:2017-06-09)

参考文献数

17

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The growth and collapse of a bubble under a floating body are simulated by using the boundary element method with linear elements to predict the damage of ship bodies induced by underwater explosion. The three-dimensional deformation of the bubble, the translation and rotation of the floating body, and the motion of water surface are taken into account in the simulation. It is shown that the bubble deforms three-dimensionally, and the liquid jet threads the bubble due to the interactions among the bubble, the floating body, and the water surface; the directions of the bubble translation and the liquid jet depend on the initial location of the bubble. The Kelvin impulse is found to be useful in evaluating the translational motion of the bubble. Also, the horizontal translational motion of the bubble is much dependent on the rotational motion of a floating body; when the moment of inertia of the floating body is small, the largest horizontal translation is realized between the axis of flotation and the edge of the floating body. It is also shown that there exists an initial horizontal bubble location where the moment of force acting on the floating body has the maximum value.