| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
It is important to understand the behaviors of large-scale solid objects transported in free-surface flows, such as debris and floating objects in flood flows and tsunamis. In this study, in order to develop a numerical method to evaluate such multiphase phenomena, three-dimensional computational method, 3D MICS, has been proposed and its validity was examined through the experimental results.
In 2005, an experimental tank, which has a wave generator, was set up to understand basic phenomena. In addition, a multiphase-flow solver, MICS, was improved to 3D. The results are summarized as follows:
(1)In the created experimental tank, fluid motions entering into dry-areas and fixed solid objects were measured.
(2)The movements of solid spheres transported by free-surface flows were captured.
(3)The multiphase-flow solver MICS was improved to three-dimensional method and it was applied to the above experimental results. As a result, the validity of the computational method was confirmed.
In 2006, the computational method, 3D MICS, was improved to the method that can deal with the non-spherical objects. Its validity was examined with experimental results. The results are summarized as follows:
(1)3D MICS was improved to the method that can deal with the non-spherical objects by treating the objects as a collection of tetrahedron elements. The collisions among the solid models are treated with contact sphere. The solid model proposed in this study is called T-type model.
(2)Tetrahedron sub-cell method was proposed to evaluate the fraction of tetrahedron elements included in a fluid-computation cell.
(3) In order to confirm the validity of the proposed computational method, it was applied to some experimental results, such as floating objects in wave motions, transportation of non-spherical objects and falling objects in water. As a result, the validity of the computational method was confirmed.
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