Everything in this world is changing from time to time by interacting with all the others, and never stays at one place and at one phase. As it were, it is a dynamical system of infinite dimensions.

あらゆるものが、この世界では相互に作用して、時々刻々その 姿を変化させ、とどまることがない。いわば無限次元の力学系とよぶことができよう。

 

四祖法語  (四祖道信大師, 580 - 651

坐禅看心 滔然得性  清虚恬静 身心調適  能安心神 窈窈冥冥  
気息清冷 徐徐斂心  神道清利 心地明浄  観察分明 内外空浄  
心性寂滅 如其寂滅  聖心顕矣 性雖無形  志節恒在 幽霊不竭  
常存朗然 是名佛性  見佛性者 永離生死   (入道安心要方便法門) 
 

坐禅を賛す   (四祖道信大師, 580 - 651)  

坐して心を看ずるには,     まず独坐して身をただす. おのずと,     
充ち流れるような自性を得る.  すがすがしく澄み,穏やかなり. 
身心を調(ととの)え かなえれば, 心神(精神) は自ずと安んずる.  
ようよう(窈窈)と吸い        めいめい(冥冥)と呼す,
息をほのかに冷静にすれば,   徐々に心がおさまる.
精神の働きは澄んでするどく,  心の様は明るくすがすしい,
よくよく観察すれば,          内も外も空にして浄,
即ち 心性は寂滅なり.    
其の寂滅のとき           聖心(妙心)まさに顕現する. 
性は無形なりと雖ども       それは流れる如く恒にあり、
幽魂は尽くることなく,        朗然たる月の如く常に存す.  
それを佛性(妙心)と名づく.
佛性を見る者は           永わに煩悩生死を離る.  
 

Verse praising Zazen Sitting    (Fourth Patriarch Daoxin Dashi, 580 - 651 
When mind is observed during sitting alone
  by straightening one's back,
one is filled with flow of sensing.
   It is cleanly empty and mildly serene. 
Settling down the body and mind properly,
  spirit is calmed.  
Breathing faintly in and unconsciously out,
  cool and clearly,  
the mind gradually settles down.
Spiritual way is clear and sharp
.  Mind state is bright and clean.
Perceiving clearly,
   one's inside and outside are empty and clean. 
Thus, mind is nirvana.
      
In such a state of nirvana,
  holy spirit (pure mind) manifests itself. 
Though its nature is of no form,
  it exists constantly as if it is flowing.
Faint spiritual soul does not run out.
  It always exists like a bright Moon.  
This is named Buddha mind.
 
Those who see Buddha mind
   are liberated eternally from worldly defilement.

 


 

   

 






portrait

神部 勉 

 Tsutomu KAMBE, Tokyo, Japan

   
Today's Weather  
今日の天気
by the Satellite View at the tenki.jp site
日本気象協会気象衛星画像 

      tenki.jp/satellite/

天候は時々刻々変化して, 雲の運動は止ることがない
Weather is changing from time to time. It never stops.


Twin typhoons over the Pacific Ocean
Satellite photograph on 29th June, 2004
(Courtesy of Japan Weather Association)

 

 
Vortex ring, made
by a half-spherical shock wave
emerging from a nozzle
(the dark object on the left).


[Shadow-graph]

Collision of two vortex rings:
Waves are emitted from two pairs of
colliding dark cores (upper and lower ends of
vertical dark bands [vortex rings]).

渦音   Vortex Sound

 

渦音   Sound generated by vortex motions   (Review paper, 2009)

Vortex sound : IJA-TK2009a,      International Journal of Aeroacoustics (2009)

Vortex sound with special reference to vortex rings:
theory, computer simulations, and experiments

By Tsutomu Kambe

 


Abstract: This is a review paper on vortex sound with special reference to vortex rings and sound emissions detected in experimental tests. Any unsteady vortex motion excites acoustic waves. From the fundamental conservation equations of mass, momentum and energy of fluid flows, one can derive a wave equation of aerodynamic sound. The wave equation of acoustic pressure can be reduced to a compact form, called the equation of vortex sound. This equation predicts sound generation by unsteady vortex motions. On the other hand, based on the matched asymptotic expansion (using the multipole expansions), one can derive a formula of wave pressure excited by time-dependent vorticity field localized in space.
The theoretical predictions are compared with experimental observations and direct computer simulations. The systems considered are, head-on collision or oblique collision of two vortex rings, vortex-cylinder interaction, vortex-edge interaction, and others. Scaling laws of the pressure of emitted sound are predicted by the theory and compared with experimental observations. Comparison between theories and observations shows excellence of the theoretical predictions. Direct numerical simulations are reviewed briefly for sound generation by collisions of two vortex rings and that by a cylinder immersed in a uniform stream (aeolian tones). Vortex sound in superfluid is also reviewed about experimental observations and computational studies on the basis of the Gross-Pitaevski equation.

 

 

 

    Full pdf-text in English :       IJA09-Vortex-Sound.pdf             

 

Stories of Bodhi-Dharma   菩提達磨の物語   (2009)

Personal memoir "Bodhi-Dharma"                                                   2009/03/01

Bodhi-Dharma   菩提達摩   (440? - 528?)

 

A collection of stories from Chinese literatures
中国の歴史資料からの達摩の物語集

By Tsutomu Kambe  
神 部  勉
(Tokyo, Japan;   March 2009)

 



Abstract:
      In August 2002, the author (T. Kambe) has been to China as a personal Buddhist pilgrim, visiting the Shao-lin Temple (
少林寺) and the Dharma Cave (達摩洞) where an Indian monk Bodhi-Dharma (菩提達摩) is said to have stayed for nine years. It was about a thousand and five hundred years ago, and the place is east of Luo-yang (洛陽) of He-nan Province (河南省), which was once a glorious capital for several dynasties. Subsequently, the author visited the Bear-Ear Mountain (熊耳山), west of Luo-yang, recorded as the Bodhi-Dharma's final resting place. When the author visited there, he had an impression that Bodhi-Dharma had been trying to return to India after he had accomplished a great mission of transmitting Dharma to his Chinese disciples. Since then, the author has been thinking about his home land. In Chinese documents, most historical articles describe that he was born in a kingdom of South India. Documents published just after Tang dynasty (唐朝 618-907) describe that the name of the Kingdom is expressed with two Chinese characters 香至.
      Very recently (November, 2007), the author came across to identify it to be Kancheepuram. The Chinese name
香至 means "fragrance extreme". At the time of Tang dynasty, it is likely that 香至 is pronounced as Kang-zhi. It is learned that Kanchee means a radiant jewel or 'a luxury belt with jewels', and Puram means a town. Then, it is understood that 香至-Kingdom corresponds to Kancheepuram.
      The author visited Kancheepuram in January 2008, wishing to find any further evidence kept in India which shows that Kancheepuram is in fact the home land of Bodhi-Dharma. Before visiting the assumed home land, this article was prepared by collecting stories of Bodhi-Dharma recorded in Chinese documents, listed at the end of this article. Most of them were published more than a thousand years ago.
      To a surprise of the author, it was informed that the Institute of Asian Studies in Chennai owns already a land in Kancheepuram and keeps it to commemorate Bodhi-Dharma and construct there a monument and an institute. It is hoped that this article is of use anyhow for the great project. The depth and broadness of Bodhi-Dharma
s influence is to be emphasized which he brought to the East land. This is exemplified by the following fact. Most frequently asked question among hundreds of Koans (公案) of Zen schools is “如何是祖師西来意 (Ru-he shi zu-shi xi-lai yi): What is the intention of Bodhi-Dharma coming from the West-land (India)? This Koan proposes encouragingly a fundamental quest for 如是 (Suchness) which Bodhi-Dharma tried to transmit to the people of East-land. This brought about revolutionary change and enlightenment in the culture of the East-land including China, Japan and other countries. “如何是祖師西来意” remains an unchanged Koan to our present age living in the 21th century.

 

 

 

    Full pdf-text in English :       Bodhi-Dharma.pdf
   
日本語テキスト :                 菩提達磨.pdf
                                       

 

 

Bodhi-Dharma took an Oceanic Silk Road from India to China !? 

達摩大師は海のシルクロードをたどって中国に至った !?   (2009)

大師の海路についての一考察                                                       2009/02/01

達摩大師と海のシルクロード

神 部  勉

元東京大学教授  (物理学)      

 



中国禅宗の祖、達摩大師がインドから中国に至るのにどのような海路をたどった のだろうか?
それは詳らかではないが、海のシルクロードをたどった可能性について
     
一説をここに提示したい。
インドと中国との間には、西暦紀元前からインド洋を横断する海洋交易が盛んで あった。
達摩大師もそのコースをたどったに違いない。
     

 

 

 

    :                
                                       

A study of sea routes of Bodhi-Dharma                                             2009/02/01

Bodhi-Dharma and Oceanic Silk Road

Tstuomu Kambe
Former Professor (Univ. of Tokyo, Physics)     

 



Bodhi-Dharma is the First Patriarch of Zen-Buddhism in China.
   However, in regard to his route from India to China, its details are not known.
      Which sea-route did Bodhi-Dharma take ?
  
In this article, a possible route is proposed to be an Oceanic Silk Road.
Already, before the Christian Era, there were active trade routes across the Indian Ocean
      between India and China.
   It is very likely that Bodhi Dharma chose this course. 

     

 

 

 

    English text :                 Sea-Route.pdf

 

 

 

 

Preprint : TK2010a:    presented at the International Workshop on 

Mathematical Fluid Dynamics (Waseda University, Tokyo),  March, 2010,

 

 Variational formulation of an ideal fluid and fluid Maxwell equations

 

by Tsutomu Kambe

 

 

 

 

Part I. Variational formulation 

There are two ways in description of fluid flows: Lagrangian description and Eulerian description. Variational formulations and Lagrangian functionals are reconsidered from the viewpoint of guage theory, i.e. expressed in a form independent of any particular coordinate system. Transformations between the two spaces are examined, and its uniqueness is considered. Importance of vorticity equation is emphasized in this regard.

                      

Part II.  Fluid Maxwell Equations

There is analogy between the equations of Fluid mechanics and Electromagnetism. Defining two vector fields analogous to the electric and magnetic fields, fluid Maxwell equations are proposed. Vorticity corresponds to the magnetic field. Equation of sound wave is derived. Hence, the sound wave is analogous to the electromagnetic wave. Forces acting on a test particle moving in a flow field are expressed with the same form as of the electromagnetism.

 

 

 

    Full pdf-text in English :       FDR-TK2010.pdf
                                    Preprint-TK2010a.pdf
               

 

 

Introductory textbook on Fluid Mechanics   (2007)

 

Elementary Fluid Mechanics

By Tsutomu Kambe

 

 

World Scientific,

 

 

 

 

This textbook describes the fundamental physical aspects of fluid flows for beginners of fluid mechanics in physics, mathematics and engineering, from the point of view of modern physics.
    It emphasizes dynamical aspects of fluid motions rather than static aspects, illustrating vortex motions, waves, geophysical flows, chaos and turbulence. Beginning with fundamental concepts of nature of flows and properties of fluids, the book presents fundamental conservation equations of mass, momentum and energy, and the equations of motion for both inviscid and viscous fluids.
    In addition to the fundamentals, this book also covers water waves and sound waves, vortex motions, geophysical flows, nonlinear instability, chaos, and turbulence. Furthermore, it includes the chapters on superfluids and the gauge theory of fluid flows. The material in the book emerged from the lecture notes for an intensive course on Elementary Fluid Mechancis for both undergraduate and postgraduate students of physics given at University of Tokyo (Japan) and at Nankai Institute of Mathematics (Tianjin, China). Hence, each chapter in the second half of the book may be presented separately as a single lecture.

 

 

 

 

 

 

Contents:

 

 

 

 

      Chap 1.   Flows
      Chap 2.   Fluids
      Chap 3.   Fundamental Equations of Ideal Fluids
      Chap 4.   Viscous Fluids
      Chap 5.   Flows of Ideal Fluids
      Chap 6.   Water Waves and Sound Waves

      Chap 7.   Vortex Motions
      Chap 8.   Geophysical Flows
      Chap 9.   Instability and Chaos
      Chap 10.   Turbulence
      Chap 11.   Superfluid and Quantized Circulation
      Chap 12.   Gauge Principle for Ideal-Fluid Flows

 

 

 

 

 

 

    Website (World Scientific) :     Elementary Fluid Mechanics

-------------------

 

 

Geometry and Dynamical systems

Revised edition of the introductory textbook (January 2010)
on Geometry of dynamical systems, fluid flows, and integrable systems.

 

Geometrical Theory of Dynamical Systems and Fluid Flows

 

By Tsutomu Kambe

Advanced Series in Nonlinear Dynamics - Vol. 23
World Scientific, 2010


 

 

This is an introductory textbook on the geometrical theory of dynamical systems, fluid flows, and certain integrable systems. The subjects are interdisciplinary and extend from mathematics, mechanics and physics to mechanical engineering, and the approach is very fundamental. The underlying concepts are based on differential geometry and theory of Lie groups in the mathematical aspect, and on transformation symmetries and gauge theory in the physical aspect. A great deal of effort has been directed toward making the description elementary, clear and concise, so that beginners will have an access to the topics.

 

 

Contents:

 

 

Part I. Mathematical Bases
      1. Manifolds, Flows, Lie Groups and Lie Algebras
      2. Geometry of Surfaces in R3
      3. Riemannian Geometry

 

Part II. Dynamical Systems
      4. Free Rotation of a Rigid Body
      5. Water waves and KdV Equation
      6. Hamiltonian systems: Chaos, Integrability and Phase Transition

 

Part III. Flows of Ideal Fluids
      7. Flows of an Ideal Fluid: Variational Formulation and Gauge Principle
      8. Volume-Preserving Flows of an Ideal Fluid
      9. Motion of Vortex Filaments

 

Part IV. Geometry of Integrable Systems
      10. Geometric Interpretations of Sine-Gordon Equation
      11. Integrable Surfaces: Riemannian Geometry and Group Theory

 

 

    Website (World Scientific) :     Geometrical Theory of Dynamical Systems and Fluid Flows
                                     

 

 

Gauge Theory of Fluid Flows  (4 papers)

Gauge theory in theoretical physics has been successfully applied to flows of an ideal fluid, and a new variational formulation is proposed. The theory is compactly summarized by the paper EE250-TK (Gauge theory 1). Detailed accounts are given by the two articles: FDR-TK2008 (Gauge theory 2) and FDR-TK2007 (Gauge theory 3) below. A new comprehensive formulation of the theory is given by the fourth paper Preprint-TK2008.

Gauge theory 1 : EE250 paper,
      published in Physica D: Nonlinear Phenomena,  237 (2008), 2067-2071.
      Proceedings of Euler Conference EE250: "Euler Equations: 250 Years On",
      held in June 2007 at Aussois, France.

Variational formulation of the motion of an ideal fluid on the basis of gauge principle

By Tsutomu Kambe

 


Abstract: On the basis of gauge principle in the field theory, a new variational formulation is presented for flows of an ideal fluid. The fluid is defined thermodynamically by mass density and entropy density, and its flow fields are characterized by symmetries of translation and rotation. A structure of rotation symmetry is equipped with a Lagrangian L including vorticity, in addition to Lagrangians of translation symmetry. From the action principle, Euler's equation of motion is derived. In addition, the equations of continuity and entropy are derived from the variations. Equations of conserved currents are deduced as the Noether theorem in the space of Lagrangian coordinate a. It is shown that, with the translation symmetry alone, there is freedom in the transformation between the Lagrangian a-space and Eulerian x-space. The Lagrangian L provides non-trivial topology of vorticity field and yields a source term of the helicity. The vorticity equation is derived as an equation of the gauge field. Present formulation provides a basis on which the transformation between the a space and the x space is determined uniquely.

 

    Full pdf-text in English :       EE250-TK-paper.pdf

 

Gauge theory 2 : FDR-TK2008,      published in Fluid Dynamics Research (2008)

Variational formulation of ideal fluid flows according to gauge principle

By Tsutomu Kambe

Fluid Dynamics Research vol.40 (2008), 399 - 426.


 

 


Abstract: On the basis of gauge principle in the field theory, a new variational formulation is presented for flows of an ideal fluid. The fluid is defined thermodynamically by mass density and entropy density, and its flow fields are characterized by symmetries of translation and rotation. Rotational transformations are regarded as gauge transformations. In addition to the Lagrangians representing translational symmetry, a structure of rotational symmetry is equipped with a Lagrangian L including vorticity. Euler's equation of motion is derived from variations according to the action principle. In addition, the equations of continuity and entropy are derived from the variations. Equations of conserved currents are deduced as the Noether theorem in the space of Lagrangian coordinate a. Without L, the action principle results in the Clebsch solution with vanishing helicity. The Lagrangian L yields non-vanishing vorticity and provides a source term of non-vanishing helicity. The vorticity equation is derived as an equation of the gauge field and the L characterizes topology of the field. The present formulation is comprehensive and provides a consistent basis for a unique transformation between the Lagrangian a space and the Eulerian x space. In contrast, with translation symmetry alone, there is an arbitrariness in the transformation between these spaces.

 

 

 

    Full pdf-text in English :       FDR-TK2008.pdf
              

Gauge theory 3 : FDR-TK2007,      published in Fluid Dynamics Research (2007)

Gauge principle and variational formulation for ideal fluids with reference to translation symmetry

By Tsutomu Kambe

Fluid Dynamics Research vol.39 (2007), 98 - 120.


 

 

Abstract: Following the gauge principle in the field theory of physics, a new variational formulation is presented for flows of an ideal fluid. In the present gauge-theoretical analysis, it is assumed that the field of fluid flow is characterized by a translation symmetry (group) and in addition that the fluid itself is a material in motion characterized thermodynamically by the mass density and entropy (per unit mass). Local gauge transformation is equivalent to local Galilean transformation. In complying with the requirement of local gauge invariance of Lagrangians, a gauge-covariant derivative with respect to time is defined by introducing a gauge term. Galilean invariance requires that the covariant derivative should be the {\it convective} derivative, \ie so-called the Lagrange derivative. Using this gauge-covariant operator, a free-field Lagrangian and a Lagrangian associated with the gauge field are defined under the gauge symmetry. Euler's equation of motion is derived from the action principle. Simutaneously, the equation of continuity and equation of entropy conservation are derived from the variational principle. It is found that general solution thus obtained is equivalent to the classical Clebsch solution. If entropy of the fluid is non-uniform, the flow will be rotational. However, if the entropy is uniform throughout the space (\ie homentropic), then the flow field reduces to that of a potential flow. Discussions are given on the issue. From global gauge invariance of the Lagrangian with respect to translational transfomations, conservation equation of momentum is deduced as Noether's theorem.

 

 

 

    Full pdf-text in English :       FDR-TK2007.pdf
              

Gauge theory 4 : Preprint-TK2008 (New paper)

 

New comprehensive formulation of the Gauge theory

Variational formulation and gauge symmetries of an ideal fluid
--- Lagrangian description and Eulerian description ---

By Tsutomu Kambe

 




Abstract: On the basis of gauge principle in the field theory, a new variational formulation is presented for flows of an ideal fluid. The fluid is defined thermodynamically by a mass density and an entropy density invariant along particle trajectories (by definition of ideal fluid). Flow fields are characterized by symmetries of translation and rotation. A Lagrangian functional is defined in terms of kinetic energy and internal energy, and the action is defined by its integral with respect to time. Noether's theorem leads to Euler's equation of motion and an energy equation. Requirement of the Lagrangian with respect to rotational gauge transformations of particle coordinates (\ie in Lagrange space) results in the invariance of vorticity transformed to the Lagrange space. This implies that the vorticity is a gauge field.
Taking into account invariances of mass, entropy and vorticity in the Lagrange space, one can introduce three additional Lagrangians of the form of total time derivative. The variational principle of the extended action leads to the the continuity equation, the entropy conservation equation, and the vorticity equation. Rotational component of velocity is defined naturally with this formulation. In addition, there exits a close relation between the helicity and the Lagrangian associated with the vorticity, both of which are regarded as Chern-Simons invariants.
Present formulation provides a basis on which the transformation between the Lagrangian space and the Eulerian space is determined uniquely. In most of traditional formualtions, the continuity equation and the entropy equaiton are taken into account as constraints by using Lagrange multiplier whose physical meaning is not clear. Thus, present formulation is consistent as a whole for description of flows of an ideal fluid.

 

 

 

    Full pdf-text in English :       Preprint-TK2008.pdf             

日本物理学会の企画『日本の物理学100年とこれから』 の依頼を受けて、 日本の物理学の歴史を、物理学の一般の分野について、その歴史 を振り返ってみる。明治初期から1930年あたりまでは 近代科学の黎明期といえる。しかしそのようなときでも、 独創的でしかも現在 でも国際的にその影響が萎えることのない研究が存在していた。

日本近代物理の私的回顧 :

「独自性の展開」 ― 物理学一般 
 

部    Tsutomu Kambe
 

「日本の物理学100年とこれから」
日本物理学会誌 2006, VOL.61, NO.3, 156-164.


 

 

Abstract: 日本の物理学の歴史100年を振り返るとき、明治初期から1930年あたりまでは黎明期 ともいえる。しかしそのようなときでも、独創的な研究が存在していた。 さらに戦後の1945年以後、日本の物理学の研究が 爆発的な勢いで質と量を増したことは、我々のよく知るところである。
 
物理学一般の分野において、独創的で、現在でもその影響が衰えることのない研究はいくつもある。 独自性のある研究をテーマにして、それらに注目してみたい。個人レベルの研究に 加えて、大型プロジェクト研究も大きな役割を果たしてきた。わが国での 「物理学一般」の研究の展開は、なかなかすてたものではないことがわかる。

 

 
 

    Full pdf-text in Japanese :       Originalities.pdf
                                     

 

 

 

Development of Originalities: Physics General in Japan  

Tsutomu Kambe

In the series " A Hundred Years of Japan Physics and Future "
Butsuri (Physics),
Phys. Soc. of Japan, 2006, VOL.61, NO.3, 156-164.


 

 

Abstract:   When we look back one hundred years of development of macroscopic physics in Japan with eyes on uniqueness, we witness a lot of studies which were original and keep its international influence even now. In addition to studies of personal level, big research projects played important parts. Those developments are reviewed in the various fields of physics general.

 

 

 

Presented at IUTAM Symposium: One HundredYears of Boundary Layer Research,
August 12 - 14, 2004, Germany.

 

Review paper :

VORTICITY IN FLOW FIELDS
in relation to Prandtl's work and subsequent developments

By Tsutomu Kambe

Preprint TK2004b.

 

 

Abstract: One of the important properties of boundary layer is, from the point of view of Stroemungslehre, that it pumps vorticity into the flow field. Vorticity in fluid flows plays diverse roles and produces tremendous variety of flow phenomena. We consider four aspects of vorticity in fluid flows: (A) Kinematical aspect of a vortex sheet, (B) mechanical aspect of hydrodynamic impulse of a vortex system, (C) dynamical aspect: vorticity dynamics, excitation of acoustic waves and formation of dissipative structure in turbulence, and (D) gauge field associated with local rotational symmetry.

 

 

 

    Full pdf-text in English :       Vorticity.pdf
                                     

 

 

SPP講義 (Science Partnership Program Lecture)
川越高等学校 (Kawagoe High School),     2004612

 

講義ノート(Lecture Note in Japanese :
 
          高校生のための物理学講義   (Physics lecture for high-school students)
 

物理学とはどういう学問なのか

What kind of science is the Physics ?

神部 勉 (Tsutomu Kambe)

 

 

 

1. はじめに
     
宇宙ニュートリノ, 自然科学の歴史

 

2. 宇宙ニュートリノの検出と超新星爆発のシナリオの検証
     
星の進化、超新星、元素合成のシナリオ

 

3. ニュートンの運動方程式はどの時刻どの場所でも成りたつ
     
不変性の原理

 

4. 膨張宇宙、赤方偏移、ハッブルの法則

 

5. ビッグバン名残りの宇宙背景放射

 

6. 重力の法則、ブラックホール、光線の湾曲

 

7. 気象現象と決定論的カオス

 

 

 

    Full text in Japanese :       SPP-Physics.pdf
                                     

 

 

Essay :

その発見はどのように役立つでしょうか?
What is the use of this discovery ?

神部 勉 (2001)

『学術の動向』20015月号


 

 

20012月に公開されたヒトゲノム解析は、この年を21世紀の単なる 最初の年以上の新時代的意味をもたせることになるであろう。

The genome sequencing published open in February 2001 would make the year a new age, more than the first year of the 21st century.

 

 

 

  Full pdf-text in Japanese :     What.pdf
                                What is the use of this discovery ?

        

 

 

Gauge theory of physics has been applied to flows of an ideal fluid.

 

Original paper on gauge theory :

Gauge principle and variational formulation for flows of an ideal fluid

By T. Kambe

Acta Mechanica Sinica, vol.19, No.5, 437-452 (2003).


 

 

1. Introduction

 

2. Conceptual scenario of the gauge principle

 

3. Preliminary study of velocity field

 

4. Free-field Lagrangian of fluid flows

 

5. Local gauge transformation

 

6. Hamilton's principle under isentropic material variations
      6.1 Flows of an ideal fluid
      6.2 Lagrangian and variational formulation
      6.3 Material variation
      6.4 Noether's theorem
      6.5 Particle-permutation symmetry and conservation equation
      6.6 Equation of vorticity and Kelvin's circulation theorem

 

7. Summary and conclusions

 

 

    Full pdf-text in English :       GaugeTheory-RotatnlSymmtry.pdf
                                     

 

What is gauge principle in fluid flows ?


Brief Communication :

Gauge principle for flows of an ideal fluid

By T. Kambe

Fluid Dynamics Research, vol.32, 193-199 (2003).


 

 

Abstract: A gauge principle is applied to flows of a compressible ideal fluid. First, a free-field Lagrangian is defined with a constraint condition of continuity equation. The Lagrangian is invariant with respect to global SO(3) gauge transformations as well as Galilei transformation. From the variational principle, we obtain the equation of motion for a potential flow. Next, in order to satisfy local SO(3) gauge invariance, we define a gauge field and a gauge-covariant derivative. Requiring the covariant derivative to be Galilei-invariant, it is found that the gauge field coincides with the vorticity and the covariant derivative is the material derivative for the velocity. Based on the gauge principle and the gauge-covariant derivative, the Euler's equation of motion is derived for a homentropic rotational flow. Noether's law associated with global SO(3) gauge invariance leads to the conservation of total angular momentum. This provides a gauge-theoretical ground for analogy between acoustic-wave and vortex interaction in fluid dynamics and the electron-wave and magnetic-field interaction in quantum electrodynamics.

 

 

 

    Full pdf-text in English :       GaugePrinciple-FDR.pdf
                                     

 

        

Reviews on physics of flow-acoustics, vortex sound and sound scattering.

 

 解説(Reviews in Japanese :

流れと音の物理

Physics of Flow-Acoustics

神部 勉

『ながれ』日本流体 力学会誌   第203 (20016)


 

 

1. はじめに

 

2. 空力音の理論 
      2.1
ライトヒル方程式
      2.2
遠方場
      2.3
スケール則

 

3. 流れによる音の発生(非線形機構)

 

4. 粘性効果

 

5. 渦音: Vortex sound
      5.1
理論
      5.2
実験
      5.3
直接数値シミュレーション

 

6. 2重極音
      6.1
エオルス音 Aeolian tone
      6.2
実験

 

7. エッジ音 Edgetone

 

8. 音のファラデーの法則

 

9. 音波の散乱 Scattering

 

10. おわりに

 

 

      Full text in Japanese
              流れと音の物理

 

Tsutomu KAMBE

神 部   

kambe@ruby.dti.ne.jp

 

HigashiYama 2-11-3, Meguro-ku
Tokyo 153-0043, Japan

153-0043 東京都目黒区東山2−11−3
                     
 

Visiting Professor, Chern Institute of
Mathematics (Tianjin, China)
 
 

南開大学(天津、中国) 陳省身数学研究所
       
客員教授 (2003 -   )
                   

Former Professor (Physics), University of Tokyo

(2000年退官)東京大学教授(物理学、流体力学)

 

川越高等学校卒業(埼玉県立)

Former Member of IUTAM Bureau (2004 - 2008)

元国際理論応用力学連合理事 (2004 - 2008)    

Former Editor-in-Chief : Fluid Dynamics Res.

Fluid Dynamics Research 編集長 (1991 - 2002

 

 

http://counter.purple.dti.ne.jp/cgi-bin/Count.cgi?df=kambe.00.dat|dd=B