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A billiard problem arising from self-propelling particles

Research Project

Project/Area Number 19K03626
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 12040:Applied mathematics and statistics-related
Research InstitutionKyoto University

Principal Investigator

Miyaji Tomoyuki  京都大学, 理学研究科, 准教授 (20613342)

Co-Investigator(Kenkyū-buntansha) SINCLAIR Robert  法政大学, 経済学部, 客員教授 (50423744)
Project Period (FY) 2019-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Keywords自己駆動粒子 / 数理モデリング / ビリヤード問題 / 力学系 / 微分方程式 / 数値シミュレーション
Outline of Research at the Start

非線形・非平衡現象によって自己組織的に駆動力を獲得して動く自己駆動的な剛体円板を有界領域に閉じ込めると,ビリヤードのような直進・反射運動が観察される.その反射規則は光の反射と異なり,反射角が入射角より大きくなるようである.その結果,領域を動き回る円板の軌道もまた完全弾性反射によるものとは異なる様相を示すと考えられる.本研究では円板と領域のサイズ比に応じた異なるレベルの数理モデルを通じて,その階層間の関連に着目しながら,反射規則という局所的な規則と円板の描く軌道という大域的なパターンとの関係の数理的理解を目指す.

Outline of Final Research Achievements

We studied the billiard-like motion of a single self-propelled particle that is asymptotically in constant velocity linear motion inside a domain and interacts repulsively with the boundary. We have conducted mathematical and numerical analyses on three different mathematical models: partial differential equation models, ordinary differential equation models, and discrete-time dynamical system models. The published results concern the reflection of particles in the ordinary differential equation model. We have proved under certain assumptions that the angle of reflection is greater than that of incidence. Numerical results suggest that this assumption can be relaxed, but the proof remains difficult. In addition, we have carried out detailed numerical experiments and have obtained a conjecture about the specific form of the functional relationship between the angle of incidence and that of reflection in the limit of very slow particle motion.

Academic Significance and Societal Importance of the Research Achievements

本研究は水面に浮かぶ樟脳円板の運動を主な動機付けとしてきたが,入射角と反射角の関係に関して得られた成果は,偏微分方程式モデルから分岐理論による縮約方程式として導かれたモデルの研究を通して得たものである.そのため,特定の方程式や系にとどまらず,同様の振る舞いを示す別の系においても同様のことが成り立つ普遍性があると予想する.我々の提出した予想を数学的に証明する試みが,自己駆動粒子の数理モデルに対する数学解析をさらに促進することを期待する.

Report

(6 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (7 results)

All 2023 2022 2020 2019

All Journal Article (2 results) (of which Peer Reviewed: 2 results,  Open Access: 1 results) Presentation (5 results) (of which Invited: 4 results)

  • [Journal Article] Asymptotic reflection of a self-propelled particle from a boundary wall2023

    • Author(s)
      Miyaji Tomoyuki、Sinclair Robert
    • Journal Title

      Japan Journal of Industrial and Applied Mathematics

      Volume: 41 Issue: 1 Pages: 269-295

    • DOI

      10.1007/s13160-023-00602-w

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Reflection of a self-propelling rigid disk from a boundary2019

    • Author(s)
      Shin-Ichiro Ei, Masayasu Mimura, and Tomoyuki Miyaji
    • Journal Title

      Discrete & Continuous Dynamical Systems - S

      Volume: 0 Issue: 3 Pages: 0-0

    • DOI

      10.3934/dcdss.2020229

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] A conjecture on the asymptotic reflection rule of a self-propelled particle2023

    • Author(s)
      Tomoyuki Miyaji and Robert Sinclair
    • Organizer
      日本数学会2023年度年会
    • Related Report
      2022 Research-status Report
  • [Presentation] 樟脳運動の粒子モデルにおける反射規則2022

    • Author(s)
      宮路智行
    • Organizer
      非線形現象の数値シミュレーションと解析ミニ研究集会2022
    • Related Report
      2022 Research-status Report
    • Invited
  • [Presentation] 非線形・非平衡系におけるビリヤード問題について2020

    • Author(s)
      宮路智行
    • Organizer
      第5回東京大学数理情報学談話会
    • Related Report
      2020 Research-status Report
    • Invited
  • [Presentation] A billiard problem of a self-propelling particle2020

    • Author(s)
      宮路智行
    • Organizer
      第6回理論応用力学シンポジウム
    • Related Report
      2020 Research-status Report
    • Invited
  • [Presentation] 非線形非平衡系におけるビリヤード問題について2019

    • Author(s)
      宮路智行
    • Organizer
      語ろう「数理解析」セミナー
    • Related Report
      2019 Research-status Report
    • Invited

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Published: 2019-04-18   Modified: 2025-01-30  

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