Updated on 2024/09/30

Information

 

写真a

 
WALL PATRICK DARREN
 
Organization
Faculty of Engineering Associate Professor
Graduate School of Engineering Department of Aeronautics and Astronautics(Concurrent)
Title
Associate Professor
Profile
Engaging in research in applied mathematics, particularly in dynamical systems and their application to fluid dynamics. This latter activity is directed towards understanding the transition of shear flows from laminar to turbulent regimes, and understanding the mechanisms that sustain turbulence, together with understanding mechanisms related to rotation, variable density and viscosity. In education I am designing and delivering a number of mathematics courses, from 1st year to the 3rd year of the undergraduate program. I also am actively engaged in promoting the internationalisation of Kyushu university.
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Degree

  • Ph. D. (Maths)

Research Interests・Research Keywords

  • Research theme: 1) In the area of fluid dynamics, investigating the transition of shear flows their associated turbulent mechanisms 2) Applying elasticity theory to understanding wire fragmentation phenomena 3) Developing alternating direction implicit methods to solve parabolic partial differential equation systems

    Keyword: dynamical systems, bifurcation, turbulence, channel flow, boundary-layer flow, alternating direction implicit methods, spectral methods

    Research period: 2018.4

Papers

  • Onset of vortex structures in rotating plane Couette flow Invited Reviewed International journal

    Masato Nagata Baofang Song Darren P. Wall

    JOURNAL OF FLUID MECHANICS   918   2021.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    Two new flows, a tilted-vortex flow and a periodic-vortex flow, are found numerically at the onset of instability in rotating plane Couette flow (RPCF). It has hitherto been believed that the first few bifurcation sequences from the laminar state are quite well understood, namely, that a streamwise-independent flow with a two-dimensional roll-cell (2dRC) structure bifurcates first, followed by the bifurcation of a wavy-vortex flow (WVF). The present study shows that the 2dRC is, in fact, unstable from its onset, and that the newly found tilted-vortex flow takes over in place of 2dRC. It is further found that the periodic-vortex flow takes part in the early stages of laminar–turbulent transition. The existence of the new flows can be verified by careful examinations of the experimental observations in Hiwatashi et al. (Phys. Fluids, vol. 19, 2007, 048103) and Kawata & Alfredsson (J. Fluid Mech., vol. 791, 2016, 191–213).

    DOI: 10.1017/jfm.2021.283

    Repository Public URL: https://hdl.handle.net/2324/7236444

  • Exact coherent states in channel flow Reviewed International journal

    WALL, D. P. & NAGATA, M.

    J. Fluid Mech.   788   444 - 468   2016.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    Three spatially extended travelling wave exact coherent states, together with one
    spanwise-localised state, are presented for channel flow. Two of the extended flows
    are derived by homotopy from solutions to the problem of channel flow subject
    to a spanwise rotation investigated by Wall & Nagata (J. Fluid Mech., vol. 727,
    2013, pp. 523–581). Both these flows are asymmetric with respect to the channel
    centreplane, and feature streaky structures in streamwise velocity flanked by staggered
    vortical structures. One of these flows features two streak/vortex systems per spanwise
    wavelength, while the other features one such system. The former substantially
    reduces the value of the lowest Reynolds number at which channel flow solutions
    ,other than the basic flow, are known to exist down to 665. The third flow has, in
    contrast, half-turn rotational symmetry about a streamwise axis through a point on the
    channel centreplane, and is found to be the flow from which one of the asymmetric
    flows bifurcates in a symmetry-breaking bifurcation. This flow is found to exist on an
    isolated bifurcation branch, whose upper and lower branches both lie on the boundary
    basin separating initial conditions that lead to turbulent events, and those that directly
    decay back to laminar flow. The structure of this flow, in which the disturbance to
    the basic flow is concentrated in a core region in a spanwise period, allowed the
    derivation of a corresponding spanwise-localised flow, which is also discussed.

    DOI: 10.1017/jfm.2015.685

    Repository Public URL: https://hdl.handle.net/2324/7236476

Presentations

  • Transition in rotating plane Couette flow International conference

    MASATO NAGATA, BAOFONG SONG, D. P. WALL

    Proc. of the 17th European Turbulence Conference  2019.9 

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    Event date: 2020.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Torino   Country:Italy  

  • Bifurcation in rotating plane Couette flow International conference

    MASATO NAGATA, BAOFONG SONG, D. P. WALL

    Bifurcations and Instabilities in Fluid Dynamics Association  2019.7 

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    Event date: 2020.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Limerick   Country:Ireland  

    The problem of transition from laminar flow to turbulence in plane Couette flow subject to a span-wise system rotation is considered,
    where the fluid motion is governed by two non-dimensional parameters, R (shear-induced Reynolds number) and Ω (system rotation
    rate). This system has long been serving as a testing ground for comparing experimental and theoretical results towards
    understanding mechanisms of transition in fluid dynamics.
    It is believed that the basic laminar state first loses stability to stream-wise independent disturbances with increasing R and/or Ω,
    resulting in the onset of a secondary flow with a stream-wise independent roll-cell structure (TV1), followed by successive
    supercritical bifurcations originating from three-dimensional instabilities of TV1. In the present paper, we re-examine this seemingly
    well-known instability property of TV1, especially for small R, and find some unexpected result.
    We shall demonstrate that the solution branch for a three-dimensional tertiary flow with small stream-wise wavenumbers resulting
    from the afore-mentioned secondary instability connects with the so-called Ribbon flow, which is composed of two tilted vortex flows,
    elongated in the stream-wise direction with the same but opposite tilted angles.
    Similar to TV1 this Ribbon flow bifurcates from the laminar basic state, and we find the bifurcation point coincides with that of TV1
    in the limit of vanishing stream-wise wavenumber.
    Thus, the stream-wise independent secondary flow, TV1, becomes unstable to disturbances with small stream-wise wavenumbers
    as soon as it bifurcates from the basic state, and so no stable stream-wise independent roll-cell structures can exist.
    We conclude that the roll-cells, which are observed in experiments as the secondary flow, might actually be a three-dimensional
    tilted vortex flow with long stream-wise wave lengths, which exists intrinsically, being independent of the different types of boundary
    condition at the sides in experiments.

  • Transition in Rotating Plane Couette Flow, Revisited International conference

    MASATO NAGATA, BAOFONG SONG, D. P. WALL

    International Union of Theoretical and Applied Mechanics (IUTAM)  2019.9 

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    Event date: 2020.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Imperial College, London   Country:United Kingdom  

  • Secondary instability of rotating plane Couette flow revisited International conference

    M. Nagata D. Wall T. Noguchi

    12th European Fluid Mechanics Conference  2018.9 

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    Event date: 2019.9

    Language:English  

    Venue:Vienna   Country:Austria  

  • BIFURCATION IN ROTATING PLANE COUETTE FLOW REVISITED International conference

    B. Song D. P. Wall M. Nagata

    European mechanics Society (Euromech) Colloquium 598  2018.8 

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    Event date: 2018.8

    Language:English  

    Venue:Imperial College, London   Country:United Kingdom  

  • Bifurcation in rotating plane Couette flow revisited International conference

    M. Nagata D. P. Wall T. Noguchi

    20th International Couette Taylor Workshop  2018.7 

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    Event date: 2018.7

    Language:English  

    Country:France  

    Repository Public URL: https://hdl.handle.net/2324/7236477

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Professional Memberships

  • 日本数学会

  • 日本応用数理学会

  • 日本流体力学会

Research Projects

  • The strato-rotational instability of channel flows

    Grant number:21K03878  2021 - 2023

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Principal investigator  Grant type:Scientific research funding

  • Exact coherent states in channel flow

    Grant number:18K03951  2018 - 2020

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Principal investigator  Grant type:Scientific research funding

Educational Activities

  • My educational activities are principally based around teaching courses related to applied mathematics and physics, alongside educational activities designed to promote internationalisation.
    Mathematics/ Physics classes currently taught:
    (1st Year) Calculus I,II,III,IV
    (1st Year) Fundamental Physics III, IV
    (2nd Year) Fluid Mechanics IIA, IIB
    (3rd Year) Mathematical Engineering I, II
    (3rd Year) Aeronautical Engineering IA
    (Master's) An introduction to dynamical systems

    Internationalisation related courses:
    Q2PEC preparation lectures
    ELEP preparation lectures

Class subject

  • (IUPE)Engineering Mathematics II

    2023.12 - 2024.2   Winter quarter

  • Calculus Ⅱ

    2023.12 - 2024.2   Winter quarter

  • 動的システム入門

    2023.10 - 2024.3   Second semester

  • (IUPE)Aerospace Engineering IA

    2023.10 - 2023.12   Fall quarter

  • Calculus Ⅰ

    2023.10 - 2023.12   Fall quarter

  • (IUPE)Engineering Mathematics I

    2023.10 - 2023.12   Fall quarter

  • (IUPE)Fluid Mechanics ⅡB

    2023.6 - 2023.8   Summer quarter

  • Calculus Ⅳ

    2023.6 - 2023.8   Summer quarter

  • (IUPE)Fluid Mechanics ⅡA

    2023.4 - 2023.6   Spring quarter

  • Calculus Ⅲ

    2023.4 - 2023.6   Spring quarter

  • (IUPE)Engineering Mathematics II

    2022.12 - 2023.2   Winter quarter

  • Calculus Ⅱ

    2022.12 - 2023.2   Winter quarter

  • Introduction to Dynamical Systems

    2022.10 - 2023.3   Second semester

  • 動的システム入門

    2022.10 - 2023.3   Second semester

  • 動的システム序論

    2022.10 - 2023.3   Second semester

  • (IUPE)Engineering Mathematics I

    2022.10 - 2022.12   Fall quarter

  • Calculus Ⅰ

    2022.10 - 2022.12   Fall quarter

  • Calculus Ⅰ

    2022.10 - 2022.12   Fall quarter

  • (IUPE)Aerospace Engineering IA

    2022.10 - 2022.12   Fall quarter

  • (IUPE)Aerospace Engineering IB

    2022.10 - 2022.12   Fall quarter

  • Calculus Ⅳ

    2022.6 - 2022.8   Summer quarter

  • (IUPE)Fluid Mechanics ⅡB

    2022.6 - 2022.8   Summer quarter

  • Calculus Ⅲ

    2022.4 - 2022.6   Spring quarter

  • (IUPE)Fluid Mechanics ⅡA

    2022.4 - 2022.6   Spring quarter

  • Calculus Ⅱ

    2021.12 - 2022.2   Winter quarter

  • (IUPE)Engineering Mathematics II

    2021.12 - 2022.2   Winter quarter

  • 専門英語

    2021.10 - 2022.3   Second semester

  • 動的システム入門

    2021.10 - 2022.3   Second semester

  • Introduction to Dynamical Systems

    2021.10 - 2022.3   Second semester

  • 専門英語

    2021.10 - 2022.3   Second semester

  • Introduction to dynamical systems

    2021.10 - 2022.3   Second semester

  • Calculus Ⅰ

    2021.10 - 2021.12   Fall quarter

  • (IUPE)Aerospace Engineering IA

    2021.10 - 2021.12   Fall quarter

  • (IUPE)Aerospace Engineering IB

    2021.10 - 2021.12   Fall quarter

  • (IUPE)Aerospace Engineering I

    2021.10 - 2021.12   Fall quarter

  • (IUPE)Engineering Mathematics I

    2021.10 - 2021.12   Fall quarter

  • Calculus Ⅳ

    2021.6 - 2021.8   Summer quarter

  • (IUPE)Fluid Mechanics ⅡB

    2021.6 - 2021.8   Summer quarter

  • Calculus Ⅲ

    2021.4 - 2021.6   Spring quarter

  • (IUPE)Fluid Mechanics ⅡA

    2021.4 - 2021.6   Spring quarter

  • Aerospace Engineering IB

    2020.12 - 2021.2   Winter quarter

  • (IUPE)Engineering Mathematics II

    2020.12 - 2021.2   Winter quarter

  • Calculus Ⅱ

    2020.12 - 2021.2   Winter quarter

  • (IUPE)Aerospace Engineering IA

    2020.10 - 2020.12   Fall quarter

  • (IUPE)Aerospace Engineering IB

    2020.10 - 2020.12   Fall quarter

  • (IUPE)Aerospace Engineering I

    2020.10 - 2020.12   Fall quarter

  • (IUPE)Engineering Mathematics I

    2020.10 - 2020.12   Fall quarter

  • Calculus Ⅰ

    2020.10 - 2020.12   Fall quarter

  • (IUPE)Fluid Mechanics ⅡB

    2020.6 - 2020.8   Summer quarter

  • Calculus Ⅳ

    2020.6 - 2020.8   Summer quarter

  • (IUPE)Fluid Mechanics ⅡA

    2020.4 - 2020.6   Spring quarter

  • Calculus Ⅲ

    2020.4 - 2020.6   Spring quarter

  • Calculus Ⅱ

    2019.12 - 2020.2   Winter quarter

  • Calculus Ⅱ

    2019.12 - 2020.2   Winter quarter

  • Aerospace Engineering I A

    2019.10 - 2019.12   Fall quarter

  • (IUPE)Eng Mathematics

    2019.10 - 2019.12   Fall quarter

  • Calculus Ⅰ

    2019.10 - 2019.12   Fall quarter

  • Calculus Ⅰ

    2019.10 - 2019.12   Fall quarter

  • Calculus Ⅳ

    2019.6 - 2019.8   Summer quarter

  • 国際オープンマインド入門

    2019.4 - 2019.9   First semester

  • Calculus Ⅲ

    2019.4 - 2019.6   Spring quarter

  • Calculus Ⅱ

    2018.12 - 2019.2   Winter quarter

  • Engineering Mathematics

    2018.10 - 2019.3   Second semester

  • Calculus Ⅰ

    2018.10 - 2018.12   Fall quarter

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FD Participation

  • 2019.12   Role:Participation   Title:New approaches to STEM edutcation - 'How to Flip a Classroom and land on your feet' (Workshop)

    Organizer:[Undergraduate school/graduate school/graduate faculty]

  • 2019.12   Role:Moderator   Title:New teaching approaches in STEM education through EMI

    Organizer:Undergraduate school department

Participation in international educational events, etc.

  • 2022.9

    UKJEEL

    9th UKJEEL Workshop, 2022

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    Venue:Durham University, U.K.

  • 2018.9

    Eight-University Engineering Association and 6U-Happier

    UK-Japan Engineering Education League Workshop

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    Venue:Fukuoka City, Japan

    Number of participants:77

Outline of Social Contribution and International Cooperation activities

  • Organiser of the 6th UK-Japan Engineering Education League Workshop
    Fukuoka, September 3rd -5th, 2018
    (Editor of Conference Proceedings)




    Organiser of the 9th UKJEEL workshop
    University of Durham (host), September 5th-6th, 2022
    Workshop themes:
    student track: "Engineering for a Sustainable Society"
    faculty track: "Future Postgraduate Education in Science & Engineering"

Social Activities

  • (Oita Pref. ) Super Science High School Science Presentation Day (Referee)

    Super Science High School (MEXT)  Oita Prefecture  2015.5

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    Audience:General, Scientific, Company, Civic organization, Governmental agency

    Type:Seminar, workshop