Sunao MURASHIGEProfessor
■Researcher basic information
Organization
- College of Science Department of Sciences Mathematics and Informatics
- Graduate School of Science and Engineering（Master's Program） Major in Science
- Graduate School of Science and Engineerin（Doctoral Program） Major in Complex Systems Science
- Faculty of Basic Natural Science Domain of Mathematics and Informatic
Research Areas
Research Keyword
Educational Background
External link
■Research activity information
Paper
- 〔Major achievements〕Two-dimensional stability analysis of finite-amplitude interfacial gravity waves in a two-layer fluid
Sunao Murashige and Wooyoung Choi, Lead
Journal of Fluid Mechanics, May 2022, [Reviewed] - Parasitic capillary waves on small-amplitude gravity waves with a linear shear current
Sunao Murashige and Wooyoung Choi, Lead
Journal of Marine Science and Engineering, Nov. 2021, [Reviewed] - 〔Major achievements〕Linear stability of transversely modulated finite-amplitude capillary waves on deep water
Sunao Murashige and Wooyoung Choi, Lead
Studies in Applied Mathematics, Feb. 2021, [Reviewed] - 〔Major achievements〕Stability analysis of deep-water waves on a linear shear current using unsteady conformal mapping
Lead
Journal of Fluid Mechanics, Feb. 2020, [Reviewed] - Long wave approximation using conformal mapping for large-amplitude internal waves in a two-fluid system
Sunao Murashige, Elsevier B.V.
Applied Numerical Mathematics, 2018, [Reviewed] - 〔Major achievements〕A numerical study on parasitic capillary waves using unsteady conformal mapping
Sunao Murashige; Wooyoung Choi
JOURNAL OF COMPUTATIONAL PHYSICS, Jan. 2017, [Reviewed] - A new method of convergence acceleration of series expansion for analytic functions in the complex domain
Sunao Murashige; Ken'ichiro Tanaka
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS, Mar. 2015, [Reviewed] - 〔Major achievements〕HIGH-ORDER DAVIES' APPROXIMATION FOR A SOLITARY WAVE SOLUTION IN PACKHAM'S COMPLEX PLANE
Sunao Murashige; Wooyoung Choi
SIAM JOURNAL ON APPLIED MATHEMATICS, 2015, [Reviewed] - Davies' surface condition and singularities of deep water waves
Sunao Murashige
Journal of Engineering Mathematics, 2014, [Reviewed] - Convergence rates and explicit error bounds of Hill's method for spectra of self-Adjoint differential operators
Ken'ichiro Tanaka and Sunao Murashige
Japan Journal of Industrial and Applied Mathematics, 2014, [Reviewed] - 〔Major achievements〕Numerical use of exterior singularities for computation of gravity waves in shallow water
Sunao Murashige
Journal of Engineering Mathematics, 2012, [Reviewed] - 〔Major achievements〕On tsunami and the regularized solitary-wave theory
Theodore Y. Wu and Sunao Murashige
Journal of Engineering Mathematics, 2011, [Reviewed] - Dwarf solitary waves and low tsunamis
Sunao Murashige and Theodore Y. Wu
Journal of Hydrodynamics, 2010, [Reviewed] - Computation of Floquet multipliers using an iterative method for variational equations
Yu Nureki and Sunao Murashige
IEICE Transactions of Fundamentals of Electronics, Communications and Computer Sciences, 2009, [Reviewed] - Boundary conditions for numerical stability analysis of periodic solutions of ordinary differential equations
Sunao Murashige
IEICE Transactions of Fundamentals of Electronics, Communications and Computer Sciences, 2008, [Reviewed] - 再分割アルゴリズムを用いた力学系の定常分布の数値計算
濡木 融; 村重 淳
電子情報通信学会論文誌, 2007, [Reviewed] - 写像により変換された曲線の折り返し点を用いた位相的エントロピーの計算
福島 真太朗; 村重 淳
電子情報通信学会論文誌, 2007, [Reviewed] - A practical method of numerical calculation of the mapping degree
Sunao Murashige
IEICE Transactions of Fundamentals of Electronics, Communications and Computer Sciences, 2006, [Reviewed] - 自動微分とDE公式を用いた非整数階微分の数値計算
岡山 友昭; 村重 淳, This paper proposes a new method of numerical calculation for fractional derivatives. Conventional methods using difference approximation have some defects such as rounding errors and computation time. In this paper, fractional derivatives are expressed as the combination of ordinary derivatives and integrals which are calculated using automatic differentiation and double exponential formula, respectively. Numerical examples show that the proposed method gives high-precision results with practical computational cost., The Japan Society for Industrial and Applied Mathematics
日本応用数理学会論文誌, 2006, [Reviewed] - Numerical computation of the mapping degree using computational homology
Kansaku Nakakura; Sunao Murashige
12th GAMM - IMACS International Symposium on Scientific Computing, Computer Arithmetic and Validated Numerics, SCAN 2006, Conference Post-Proceedings, 2006, [Reviewed] - 〔Major achievements〕Numerical verification of solutions of Nekrasov's integral equation
Sunao Murashige and Shin'ichi Oishi
Computing, 2005, [Reviewed] - Analysis of flagellar bending in hamster spermatozoa: characterization of an effective stroke
Kinukawa; M.; Ohmuro; J.; Baba; S.A.; Murashige; S.; Okuno; M.; Nagata; M.; and Aoki; F.
Biology of Reproduction, 2005, [Reviewed] - 〔Major achievements〕On necessary and sufficient conditions for numerical verification of double turning points
Ken'ichiro Tanaka; Sunao Murashige and Shin'ichi Oishi
Numerische Mathematik, 2004, [Reviewed] - Numerical verification of solutions of periodic integral equations with a singular kernel
Murashige; S. and Oishi; S.
Numerical Algorithms, 2004, [Reviewed] - Bifurcation structures of period-adding phenomena in an ocean internal wave model
Tanaka; G.; Murashige; S.; and Aihara; K.
International J. of Bifurcation and Chaos, 2003, [Reviewed] - Boundary element simulation of large amplitude standing waves in vessels
Hamano; K.; Murashige; S.; and Hayami; K.
Engineering Analysis with Boundary Elements, 2003, [Reviewed] - 〔Major achievements〕Nonlinear analyses of roll motion of a flooded ship in waves
Sunao Murashige; Taiji Yamada and Kazuyuki Aihara
Phil. Trans. R. Soc. Lond. A, 2000, [Reviewed] - 2次元しきい値分布を利用した流行現象の数理モデルとその解析
河根 拓文; 村重 淳; 合原 一幸
電子情報通信学会論文誌 A, 2000, [Reviewed] - Bifurcation and resonance of a mathematical model for non-linear motion of a flooded ship in waves
Sunao Murashige; Kazuyuki Aihara and Motomasa Komuro
J. of Sound and Vibration, 1999, [Reviewed] - 〔Major achievements〕Experimental study on chaotic motion of a flooded ship in waves
Sunao Murashige and Kazuyuki Aihara
Proc. R. Soc. Lond. A, 1998, [Reviewed] - Coexistence of periodic roll motion and chaotic one in a forced flooded ship
Murashige; S. and Aihara; K.
International Journal of Bifurcation and Chaos, 1998, [Reviewed] - Nonlinear Roll Motion of a Ship with Water-on-Deck in Regular Waves(Summaries of Papers Published by Staff of Ship Research Institute at Outside Organizations)
村重 淳; 合原 一幸; 山田 泰司, National Maritime Research Institute
Report of Ship Research Institute, 12 Mar. 1997 - Nonlinear roll motion of a flooded ship in regular waves, J. Society of Naval Architects of Japan
Murashige; S. and Aihara; K., This paper describes dynamic effects of flooded water on nonlinear roll motion of a ship in regular beam waves. Experiments using a ferry model demonstrate nonlinear roll response of a flooded ship in waves. It is found that two kinds of roll motion with different amplitudes and periods coexist and that one of them is particularly irregular and complicated even in regular waves of relatively moderate amplitude. The reconstructed attractor of the roll motion in a delay-coordinate state space shows that it is not simple harmonic motion. In order to further study this complicated roll motion, we derived model equations which include both the nonlinear effects of the restoring moment and the coupling effects of roll and flooded water. The dynamic motion of flooded water produces the coupling effects which have been neglected in most previous works. Numerical solutions of the model equations show that this coupled system yields nonlinear phenomena similar to the experimental results. In addition, we also experimentally studied motion of a box-shaped model with flooded water in regular waves. The experimental results show that the roll response varies with changing the wave height in a complicated manner which also depends on the amount of flooded water, and that some of complicated roll motion have typical properties of low-dimensional deterministic chaos. These results suggest that the nonlinearly coupled dynamics of a ship and flooded water is a key to solve this problem., The Japan Society of Naval Architects and Ocean Engineers
J. Society of Naval Architects of Japan, 1997, [Reviewed] - 〔Major achievements〕An ideal ocean wave focusing lens and its shape
Sunao Murashige and Takeshi Kinoshita
Applied Ocean Research, 1992, [Reviewed] - Ocean wave focusing : experiments and nonlinear computations
Murashige; S.; Kinoshita; T. and Suzuki; T.
International Journal of Offshore and Polar Engineering, 1992, [Reviewed] - Are incident waves split into symmetrical and anti-symmetrical scattering wave systems with equal energy by two dimensional obstacles?
Sunao Murashige and Takeshi Kinoshita, Kato et al. reported that a wave height of a symmetrical component and an antisymmetrical component of scattered waves is exactly one half of that of incident waves, that is, "equally energy splitting law", and that in two dimensional diffraction problems this law does not require symmetry of a body geometry. It gives us valuable information as an invariant property. In the present note, however, we show that it is invalid in the case of an asymmetrical body, although it is reviewed as valid by Kan., The Japan Society of Naval Architects and Ocean Engineers
J. Kansai Soc. N.A., Japan, 1991, [Reviewed] - 海洋波集波レンズの基礎的研究
村重 淳; 木下 健, Wave focusing has been attracting ocean engineers as one of the most promising techniques to control ocean waves. It creates a calm sea area and helps efficient utilization of wave energy. In the present work, a hydrodynamic singularity distribution which expresses a wave focusing lens is derived by the method of matched asymptotic expansion, assuming slenderness of the lens and high frequency of incident waves. The singularity distribution gives the following necessary conditions for scattered waves in each section of the lens : there is no reflection from the lens and the transmitted waves suffer a phase shift in passing the lens. The phase shift is given by the wavenumber and the distance between the section and the focus. From these conditions, we examine a sectional shape of the lens and determine the whole geometry. It is shown by experiments and numerical computations using the two dimensional doublet distribution method that a submerged chevron shape plate, which is suitably folded, scatters a wave system which satisfies the above conditions at a certain wave frequency, but not in wide band of wave frequencies because of dispersion of water waves. Then it is shown by experiments that a certain number of submerged circular cylinders,which are horizontally arranged at intervals just like a raft, transmits waves which have enough phase shift to focus waves but reflects almost no waves in wide band of wave frequencies. Finally, we examine performances of three types of lens, namely, submerged fiat plate, submerged chevron shape plate, and submerged circular cylinders, in both regular and irregular waves. It is shown by numerical computations that the wave focusing efficiency of the lens consisting of circular cylinders is about twice that of the fiat plate type lens and that the drift force acting on the former is less than half of that on the latter in irregular waves., The Japan Society of Naval Architects and Ocean Engineers
日本造船学会論文集, 1990, [Reviewed] - Singularity distribution for ocean wave focusing
Sunao Murashige and Takeshi Kinoshita
Proc. Japan Assoc. Coastal Zone Studies, 1990, [Reviewed]
Lectures, oral presentations, etc.
- 内部ボアの極限としての重力流について
海洋波の非線形運動の数理モデルと解析, 24 Mar. 2025 - Local flow structure near the separation point of gravity currents
BIRS 5-day Workshop, Nonlinear Water Waves: Rigorous analysis and Scientific Computing, 28 Oct. 2024, [Invited] - 重力流の剥離点付近の局所解について
日本流体力学会 年会2024, 26 Sep. 2024 - Improvement of Benjamin's approximate solution for gravity currents
Applied Mathematics and Data Science II, 11 Jul. 2024, [Invited]
20240710, 20240712 - A numerical study on energy-conserving gravity currents past an air cavity
Workshop on Nonlinear Water Waves and Related Topics, 10 Nov. 2023 - 重力流と内部ボアの定常解
日本流体力学会 年会2023, 22 Sep. 2023 - 〔Major achievements〕Internal fronts and gravity currents
Recent Advances in Nonlinear Water Waves, 28 Mar. 2023 - 2層流体の界面で発生する内部ボアの定常進行波解
日本流体力学会 年会2022, 27 Sep. 2022 - 線形シアー流上で発生する parasitic capillary waves の数値的研究
日本流体力学会年会2021, 23 Sep. 2021 - Effects of a linear shear current on surface waves in deep wate
Sunao Murashige
Online seminar on nonlinear water waves and related topics, 16 Jul. 2021 - 有限振幅表面張力波の3次元的線形安定性解析
村重 淳
日本流体力学会 年会2020, 20 Sep. 2020 - 等角写像を用いた表面張力波の線形安定性解析
村重 淳
RIMS 研究集会 「非線形波動現象の数理とその応用」, 17 Oct. 2019 - 等角写像を用いた大振幅・定常進行水面波の線形安定性解析
村重 淳
日本流体力学会 年会2019, 14 Sep. 2019 - 〔Major achievements〕Stability of deep-water waves with constant vorticity
Sunao Murashige
Nonlinear waves, Theory, Computations and Real-World Applications, Jan. 2019, [Invited] - 線形シアー流上を進行する周期的深水波の2次元的定常運動
村重 淳
RIMS 研究集会 「非線形波動現象の数理とその応用」, 18 Oct. 2018 - 水波問題と複素解析
村重 淳
AIMap異分野ワークショプ「海岸・海洋における非線形問題に対する数学的手法の展開 ーモデリング，解析，数値計算ー」, 06 Oct. 2018, [Invited] - 線形シアー流上を進行する水波の2次元的定常運動
村重 淳
日本流体力学会 年会2018, 06 Sep. 2018 - 〔Major achievements〕Two-dimensional stability of solitary waves on a linear shear current
Sunao Murashige
SIAM Conference on Nonlinear Waves and Coherent Structures, 11 Jun. 2018 - 〔Major achievements〕Large-amplitude solitary waves on a linear shear current
Sunao Murashige
Workshop on Nonlinear Water Waves -- In honor of Professor Mitsuhiro Tanaka on the occasion of his retirement --, 23 May 2018 - 〔Major achievements〕Large amplitude motion of periodic internal waves in a two fluid system of finite depth
Sunao Murashige
Workshop on nonlinear water waves and related phenomena, 19 Feb. 2018, [Invited] - 線形シアー流上を進行する定常水波に対する長波モデル
村重 淳
RIMS 研究集会 「非線形波動現象の数理とその応用」, 11 Oct. 2017 - 〔Major achievements〕Numerical and theoretical studies of nonlinear water waves using the hodograph transformation
Sunao Murashige
Dispersive hydrodynamics and oceanography: from experiments to theory, Aug. 2017, [Invited] - 〔Major achievements〕Long wave approximation with hodograph transformation for periodic internal waves in a two-fluid system
Sunao Murashige
The Tenth IMACS International Conference on Nonlinear Evolution Equations and Wave Phenomena: Computation and Theory, 30 Mar. 2017 - 海洋における非線形波動の数理
村重 淳
第12回数理工学セミナー, Dec. 2016, 田中 健一郎（武蔵野大学）, [Invited] - 非定常ホドグラフ変換を用いた水波の非線形運動の数値計算
村重 淳
RIMS 研究集会 「非線形波動現象の数理とその応用」, Oct. 2016, 村重 淳 - 波長の長い重力水波に対する級数展開の収束性
村重 淳
日本流体力学会 年会2016, Sep. 2016 - 〔Major achievements〕Generalization of Stokes' decay rate formula for solitary waves
Murashige; S.
Mini-Workshop on Nonlinear Waves in Fluids -- In honor of Professor Funakoshi on the occasion of his retirement --, May 2016, 村重 淳 - 非定常等角写像を用いた重力・表面張力水波の強非線形計算
村重 淳
日本流体力学会 年会2015, Sep. 2015 - 〔Major achievements〕Fully nonlinear computation of unsteady water waves using a non-stationary conformal mapping
Murashige; S.
Workshop on Nonlinear Waves and Fluid Mechanics, Aug. 2015, Wooyoung Choi (New Jersey Institute of Technology), [Invited] - Improvement of convergence of series expansion for water wave solutions
Murashige; S.
Mini-Workshop on Nonlinear Water Waves, Dec. 2014, 村重 淳 - 水面波に対する Davies 近似とその改良
村重 淳
RIMS 研究集会 「非線形波動現象のメカニズムと数理」, Oct. 2014, 田中 光宏（岐阜大学） - 孤立波に対する高次 Davies 近似について
村重 淳
日本流体力学会 年会2014, Sep. 2014 - 〔Major achievements〕Davies approximation of Levi-Civita's surface condition for water waves in the complex domain
Murashige; S.
SIAM Conference on Nonlinear Waves and Coherent Structures, Aug. 2014
Research Themes
- Mathematical models of fully nonlinear and unsteady phenomena of ocean waves and their verification
Grant-in-Aid for Scientific Research (B)
Ibaraki University
01 Apr. 2024 - 31 Mar. 2027 - Mathematical models and their verifications for fully nonlinear and unsteady motion of ocean waves
Grant-in-Aid for Scientific Research (B)
Ibaraki University
Apr. 2022 - Mar. 2027 - Mathematical models of large-amplitude and nonlinear ocean waves
Grant-in-Aid for Scientific Research (B)
Ibaraki University
Apr. 2017 - Mar. 2022 - Development of computer assisted analysis for complicated nonlinear phenomena
Grant-in-Aid for Scientific Research (S)
2008 - 2011 - Numerical computation of periodic solutions of continuous dynamical systems given by stiff ordinary differential equations
Grant-in-Aid for Scientific Research (C)
Future University-Hakodate
2007 - 2008 - Construction of a Superrobust Computation Paradigm
Grant-in-Aid for Scientific Research (S)
The University of Tokyo
2003 - 2007 - Numerical verification for nonlinear equations including a principal value integral
Grant-in-Aid for Scientific Research (C)
TEMThe University of Tokyo
2002 - 2003
