著者

山田 祥徳 酒井 幹夫 水谷 慎 越塚 誠一 大地 雅俊 室園 浩司

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.10, no.3, pp.185-193, 2011 (Released:2011-08-24)

参考文献数

21

被引用文献数

27 26

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In nuclear engineering, fluid flows involving free surface were well studied, e.g., pipe thinning produced by liquid droplet impingement, and steam explosion triggered by molten metal immersed in water. The moving particle simulation (MPS) method was often used in past studies. In this method, the Poisson equation was solved to obtain the pressure field. Solving the Poisson equation becomes a dominant process. Reducing the time of calculation of the Poisson equation is important for using the CFD in the engineering fields. Thereat, we propose a new MPS method by which the pressure field is calculated explicitly. We call it the explicit (E-)MPS method. The E-MPS method was applied to a static water and dam break problem to show its adequacy. Besides, we compare the calculation time between the E-MPS method and traditional one.

著者

酒井 幹夫 山田 祥徳 茂渡 悠介

出版者

The Society of Powder Technology, Japan

雑誌

粉体工学会誌 (ISSN:03866157)

巻号頁・発行日

vol.47, no.8, pp.522-530, 2010-08-10 (Released:2010-08-25)

参考文献数

23

被引用文献数

5 5

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The Discrete Element Method (DEM) is widely used in computational granular dynamics. The DEM is a Lagrangian approach where individual particle is calculated based on the Newton's second law of motion. Hence, the DEM enables us to investigate the granular flow characteristics at the particle level. On the other hand, the DEM has a difficulty to be used in large-scale powder systems because the calculation cost becomes too expensive when the number of particles is huge. Consequently, we have developed a coarse grain modeling as a large scale model of the DEM. The coarse grain particle represents a group of original particles. The coarse grain model was applied in typical gas-solid and solid-liquid two phase flows. The cohesive force like the van der Waals force was not considered in these simulations. In the present study, the coarse grain model is evolved to simulate the cohesive particles by considering the interparticle van der Waals force. The adequacy of the coarse grain model is proved by comparing the simulation results of original particle system. It is shown that the coarse grain model considering the interparticle force can simulate the original particle behavior precisely.

著者

柴田 和也 越塚 誠一 酒井 幹夫 谷澤 克治 辻本 勝

出版者

公益社団法人 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.11, pp.125-136, 2010 (Released:2011-01-28)

参考文献数

19

被引用文献数

1

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A transparent boundary condition was developed for calculating water waves propagating to a distant area by using a particle method. In front of the boundary, the incident waves were analyzed by Fourier analysis, and the particles on the transparent boundary were forced to move to absorb the incident waves. The characteristics of this study are to introduce the technique of wave analysis used for the wave tanks to the particle simulation and to reduce the calculation cost by employing an inflow and outflow boundary. Water waves were calculated in two wave periods by the developed transparent boundary condition. As the results, it was shown that this transparent boundary transmitted the incident waves without the reflection waves. It was also shown that the calculation cost was smaller than that of the ordinary high viscosity boundary condition.

著者

茂渡 悠介 酒井 幹夫 水谷 慎 青木 拓也 斉藤 拓巳

出版者

日本混相流学会

雑誌

混相流 (ISSN:09142843)

巻号頁・発行日

vol.24, no.5, pp.681-688, 2011-03-15 (Released:2011-06-15)

参考文献数

11

被引用文献数

3 3

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Numerical approaches of the solid-liquid flows were not established so far. This is because the modeling of free surface and solid phase was difficult, furthermore the calculation cost might become excessive. In the present study, a new method is developed to simulate the solid-liquid flows involving the free surface. In this method, the solid-liquid flows were computed by combining the Discrete Element Method (DEM) and the Moving Particle Semi-implicit (MPS) method. This is called the DEM-MPS method. In the present study, the validation of the DEM-MPS method was performed in a solid-liquid flow involving free surface in a rotating tank. The angle of repose and solid distribution were compared between the simulations and experiments. The simulation results were in good agreement with those obtained by the experiment.

著者

山田 祥徳 酒井 幹夫 水谷 慎 孫 暁松 野々上 友也 高橋 公紀

出版者

The Society of Powder Technology, Japan

雑誌

粉体工学会誌 (ISSN:03866157)

巻号頁・発行日

vol.48, no.5, pp.288-295, 2011-05-10 (Released:2011-05-31)

参考文献数

18

被引用文献数

1 1

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In industrial arena, there are many solid-liquid two phase flow systems like mixing vessels, glass furnaces, solid-liquid separation equipments, etc. Numerical simulations are promising approach to understand the phenomena. Numerical analyses by the Eulerian-Lagrangian approach were performed in the past studies. The Eulerian-Lagrangian methods were applied to various solid-liquid flow systems without the free surfaces. On the other hand, numerical models which can treat the solid-liquid flows involving free surface were hardly developed so far. Hence, in the current study, we develop a Lagrangian-Lagrangian coupling methods to perform the fast simulation of the solid-liquid flows. The liquid phase were modeled by the Explicit Moving Particle Simulation (E-MPS) method. The E-MPS method can simulate the free surface flows easily. The DEM / E-MPS method was applied to a solid-liquid flow in a pipeline. The simulations were performed by changing the acoustic velocity. The simulation results, namely, the solid particle distribution, pressure and fluid velocity were compared in the present study. The DEM / E-MPS method is shown to make possible to perform the fast simulation by assuaging the acoustic velocity.

著者

田中 正幸 酒井 幹夫 越塚 誠一

出版者

一般社団法人 日本計算工学会

雑誌

日本計算工学会論文集 (ISSN:13478826)

巻号頁・発行日

vol.2007, pp.20070007, 2007 (Released:2007-03-13)

参考文献数

20

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Many methods to simulate rigid body motion and collision have been developed in the computer graphics field recently. In most methods, polygons are used to represent a rigid body configuration. In this paper a novel particle based method is presented and some examples are calculated. A simple algorithm for collision detection is proposed using particles and Distinct Element Method (DEM) is used for collision response. In the case that a configuration of a rigid body is complicated, the quantity of data is reduced and the calculation is fast. It is also easy to couple with fluid motion using Moving Particle Semi-implicit (MPS) method.