Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants |
General mathematics (including Probability theory/Statistical mathematics)
|Research Institution||HIROSHIMA UNIVERSITY (2005)|
Kyushu University (2003-2004)
NAKAKI Tatuyuki Hiroshima University, Faculty of Integrated Arts and Sciences, Professor, 総合科学部, 教授 (50172284)
FUKUMOTO Yasuhide Kyushu University, Faculty of Mathematics, Professor, 大学院・数理学研究院, 教授 (30192727)
KIMURA Masato Kyushu University, Faculty of Mathematics, Associate Professor, 大学院・数理学研究院, 助教授 (70263358)
SUZUKI Atsushi Kyushu University, Faculty of Mathematics, Research Associate, 大学院・数理学研究院, 助手 (60284155)
OHMORI Katsushi Toyama University, Faculty of Human Development, Professor, 人間発達科学部, 教授 (20110231)
HATTORI Yuji Kyushu Institute of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (70261469)
坂上 貴之 北海道大学, 大学院・理学研究科, 助教授 (10303603)
長藤 かおり 九州大学, 大学院・数理学研究院, 助教授 (40326426)
|Project Period (FY)
2003 – 2005
Completed (Fiscal Year 2005)
|Budget Amount *help
¥12,500,000 (Direct Cost: ¥12,500,000)
Fiscal Year 2005: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2004: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 2003: ¥5,800,000 (Direct Cost: ¥5,800,000)
|Keywords||point vortex / vortex ring, vortex tube / one- or two-phase fluid problems / relaxation oscillation / instability / weakly nonlinear stability / topological chaos / flux-free finite element method / 渦糸の緩和振動 / 球面上の渦糸 / 渦輪の非線形不安定性 / らせん渦 / 理想MHDの数値解析法 / 移動・自由境界問題 / フラックス・フリー有限要素法 / ベクトル化 / 渦輪の局所安定性解析 / 質量保存型有限要素法 / 数値的検証法 / アダプティブメッシュ / 正射影付有限要素方程式|
(1) We consider problems of point vortices in a plane, which are described by the two-dimensional Euler equation. (i) Stability of relative equilibria for five point vortices is treated. We found that some unstable configurations exhibit the relaxation oscillation. Four and three point vortices which exhibit the relaxation oscillation are also found. Mathematical justifications are made. (ii) When vortices come close each other, numerical difficulty occurs. To overcome this difficulty, we propose a numerical scheme.
(2) We consider the point vortices in a sphere. When two vortices are fixed at the poles of sphere, the stability of some configuration and reduction to a center manifold are shown.
(3) Three-dimensional linear instability of vortex flow is considered. By using spectral theory with Hamiltonian, we found a primary factor of instability for some cases.
(4) To analyze the instability of vortex ring in the nonlinear region, we introduce a weakly nonlinear system by multi-scale methods. By using this system, we found the mechanism of the Windall instability and unstable modes.
(5) By singular limit methods, we propose and analyze the numerical methods to the classical one-phase Stefan problems and the flow through porous media.
(6) For immiscible two-phase flow, we consider a flux-free finite element method, which shows good conservation of mass. We obtain error estimates and convergence of numerical solution.
(7) We apply a numerical verification method to the driven cavity problem, which is one of famous two-dimensional fluid problems. We succeeded in the verification of some steady solutions.