巻号一覧
11 巻 (1997)
- 4 号 p. 332-
- 3 号 p. 211-
- 2 号 p. 115-
- 1 号 p. 3-
前身誌
11 巻, 3 号
選択された号の論文の7件中1～7を表示しています
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福嶋 祐介1997 年 11 巻 3 号 p. 211-220
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリーA numerical model of powder snow avalanches is developed based the tllermal model in the field of fluid mechanics. The model consists of theconservative equation of fluid phase, the conservative equation of the solid phase, the momentum equation and the equation of the kinetic energy of turbulence. Some constitution relationships, i. e. the entrainment coefficients of ambient fluid, the entrainment coefficient of snow particles on the bed and the shape facotors are expressed by the functions of the slope angle. This model is examined by the experimental data of inclined thermals using the mixture of water and solid particles in the laboratory. The numerical calculations are carried out to simulate the powder snow avalanche occurring at the Yokokura, Katsuyama city in Fukui Prefecture. The reasonable numerical results are obtained. It can explain the longitudinal variations of the height, the speed, the concentration of snow particles, the kinetic energy of turbulence and the distructive power of the avalanche.抄録全体を表示PDF形式でダウンロード (1226K) -
大場 謙吉1997 年 11 巻 3 号 p. 221-229
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリーThis paper expounds some important functional multiphase fluids which are related to biological and medical systems. Artificial blood or blood substitute, gel-dispersed fluid, micro capsule dispersed fluid for the intelligent drug delivery system, micelle of liquid crystal, liquid crystal dispersed fluid and thixotropic fluid are explained and their characteristics and applications are discussed.抄録全体を表示PDF形式でダウンロード (2879K) -
第2報: 気泡生成頻度に及ぼすガス吹込み方向とノズル内乱流遷移の影響井口 学, 千原 知幸, 横谷 真一郎1997 年 11 巻 3 号 p. 230-236
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリーGas was injected into a bath through a nozzle attached to an immersed top lance. The injection angle was changed from zero (upward injection) to π/2 (horizontal injection) to investigate the effect of injection angle on the frequency of bubble formation. In the case of upward injection, the direction of the inertia force of injected gas and that of the buoyancy force acting on the injected gas is the same, while in the case of horizontal injection, the two directions are perpendicular to each other. The frequency of bubble formationfB was significantly influenced by the injection angle. It increased monotonically as the injection angle increased from 0 to π/2. An empirical equation was derived for correlating measuredfB data. In addition, the effect of turbulence transition in nozzle flow on the frequency of bubble formation was discussed.抄録全体を表示PDF形式でダウンロード (1807K) -
第2報: 2流体モデル方程式系について棚町 芳弘, 霜田 善道, 藪下 幸久, 標 宣男1997 年 11 巻 3 号 p. 237-249
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリーThe aim of this papar is to show the mechanism of instability of the Finite Difference Equation (FDE) for a linearized system of Two Fluid Model (TFM) equations by means of the eigenvalues of the coefficient matrix in the modified equation. First, the modified equations of FDE are introduced from the FDE which was obtained by discretizing the linearized system using the two step Lax-Wendroff scheme. Then, we make sure from the modified equations that the instability of the FDE is caused by ill-posedness of original TFM equation system. Furthermore, von Neumann's stability discriminant equation is concretely and analytically expressed by the sum of damping term and growing term, which consist of numerical diffusion from its lowest even order derivative term of the modified equation, and complex eigenvalue due to ill-posedness of the system, respectively. Finally, the influence of these two terms on the stability is directly shown for the various spatial grid sizes.抄録全体を表示PDF形式でダウンロード (1433K) -
森永 栄二, 鮎川 恭三, 越智 順治, 河原 源太1997 年 11 巻 3 号 p. 250-257
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリーThis papar is concerned with numerical simulation of a bubbly flow which is generated by continuous release of bubbles with various arrangements from the bottom of a vessel in gravitational field. The flow was analyzed as a continuum in which density and viscosity changed owing to existence of the bubbles. The availability of the exact solution of B. B. O.'s equation with constant acceleration during small time interval made it easy to analyze the motion of the bubbles in the flow. The velocity and pressure fields based on one fluid model were calculated using the SIMPLE method. For initially asymmetric arrangement of bubbles or asymmetric release position, the flow tends to be unstable, even if asymmetry is slight. For initially symmetric arrangement, small bubbles, released from symmetric bottom position of a vessel, are caught in vortices generated by rising bubbles and the flow. tends also to be unstable because of the slight difference of number density of the bubbles in the vortices. This tendency becomes to be weak when large bubbles are mixed with the small bubbles.抄録全体を表示PDF形式でダウンロード (8365K) -
2. 掃流状集合流動江頭 進治1997 年 11 巻 3 号 p. 258-262
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリー第1回目は土石流の力学に関する研究成果について解説した。ここでは、それに引き続き掃流状集合流動あるいは土砂流と呼ばれている流れについて解説する。土石流の解説 [1] において勾配がある限界値よりも大きい場合には、砂礫と水との混合物の流れは、巨視的には水と砂礫とは一体になって流れるが、勾配が限界値よりも緩くなると、自由水面近傍には砂礫を含まない水の流れが形成される。このような流れを土砂流あるいは掃流状集合流動と呼んでいる。したがって、一流体モデルによる解析においては、上層の流れは通常の清水流の応力モデルが適用でき、下層の流れには、土石流のものが直接適用できる。なお、以下の議論は、あくまで平均流に関するものである。抄録全体を表示PDF形式でダウンロード (546K) -
大成 博文1997 年 11 巻 3 号 p. 263-266
発行日: 1997/09/15
公開日: 2011/02/22
ジャーナル フリーTwo water purification techniques in wide-closed water area polluted by waste water were developed using two types of aeraters which could generate a large quantity of micro-bubbles, which diameters are less than 100 micron, and form large-scale circulating secondary flows in the whole water area. The efficiency of the techniques was experimentally proved for two kinds of waste water quality in fields.The results indicate that the both aeration systems play a great important role of waste water purification and the growth of animals and plants.抄録全体を表示PDF形式でダウンロード (7317K)
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