• Title/Summary/Keyword: Eigenvalue Branches

Search Result 10, Processing Time 0.023 seconds

Gravitational Effect on Eigenvalue Branches and Flutter Modes of a Vertical Cantilevered Pipe Conveying Fluid (유체 이송 연직 외팔 송수관의 고유치분기와 플러터 모드에 미치는 중력 효과)

  • Ryu Si-Ung;Shin Kwang-Bok;Ryu Bong-Jo
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.23 no.4 s.181
    • /
    • pp.67-74
    • /
    • 2006
  • The paper presents gravitational effect on eigenvalue branches and flutter modes of a vertical cantilevered pipe conveying fluid. The eigenvalue branches and modes associated with flutter of cantilevered pipes conveying fluid are fully investigated. Governing equations of motion are derived by extended Hamilton's principle, and the related numerical solutions are sought by Galerkin's method. Root locus diagrams are plotted for different values of mass ratios of the pipe, and the order of branch in root locus diagrams is defined. The flutter modes of the pipe at the critical flow velocities are drawn at every one of the twelfth period. The transference of flutter-type instability from one eigenvalue branches to another is investigated thoroughly.

Eigenvalue Branches and Flutter Modes of a Cantilevered Pipe Conveying Fluid and Having a Tip Mass (말단질량을 갖는 외팔 송수관의 고유치 분기와 플러터 모드)

  • Ryu, B.J.;Ryu, S.U.;Lee, J.W.
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.13 no.12
    • /
    • pp.956-964
    • /
    • 2003
  • The paper describes the relationship between the eigenvalue branches and the corresponding flutter modes of cantilevered pipes with a tip mass conveying fluid. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The flutter configurations of the pipes at the critical flow velocities are drawn graphically at every twelfth period to define the order of quasi-mode of flutter configuration. The critical mass ratios, at which the transference of the eigenvalue branches related to flutter takes place. are definitely determined. Also, in the case of haying internal damping, the critical tip mass ratios, at which the consistency between eigenvalue braches and quasi-modes occurs. are thoroughly obtained.

Eigenvalue Branches and Flutter Modes of Pipes with a Tip Mass Conveying Fluid (끝단질량을 갖는 송수관의 고유치 분기와 플러터 모드)

  • 류봉조;류시웅;빈산길언;임경빈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2003.05a
    • /
    • pp.665-669
    • /
    • 2003
  • The paper deals with the relationship between the eigenvalue branches and the corresponding flutter modes of cantilevered pipes with a tip mass conveying fluid. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The order of branches and unstable modes associated with flutter are defined in the stability maps of mass ratios of the pipe and the critical flow velocity. As a result, the relationship between the flutter related to the eigenvalue branches and the flutter modes are investigated thoroughly.

  • PDF

Gravitational Effect on Dynamic Stability of a Vertical Cantilevered Pipe Conveying Fluid (유체 이송 연직 외팔송수관의 동적안정성에 미치는 중력 효과)

  • 류봉조;류시웅
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.174-179
    • /
    • 2004
  • The paper deals with gravitational effect on dynamic stability of a cantilevered pipe conveying fluid. The eigenvalue branches and modes associated with flutter of cantilevered pipes conveying fluid are fully investigated. Governing equations of motion are derived by extended Hamilton's principle, and the solutions are sought by Galerkin's method. Root locus diagrams are plotted for different values of mass ratio of the pipe, and the order of branch in root locus diagrams is defined. The flutter modes of the pipe at the critical flow velocities are drawn at every one of the twelfth period. The transference of flutter-type instability from one eigenvalue branches to another is investigated thoroughly.

  • PDF

Vibration and Dynamic Stability of Pipes Conveying Fluid on Elastic Foundations

  • Ryu, Bong-Jo;Ryu, Si-Ung;Kim, Geon-Hee;Yim, Kyung-Bin
    • Journal of Mechanical Science and Technology
    • /
    • v.18 no.12
    • /
    • pp.2148-2157
    • /
    • 2004
  • The paper deals with the vibration and dynamic stability of cantilevered pipes conveying fluid on elastic foundations. The relationship between the eigenvalue branches and corresponding unstable modes associated with the flutter of the pipe is thoroughly investigated. Governing equations of motion are derived from the extended Hamilton's principle, and a numerical scheme using finite element methods is applied to obtain the discretized equations. The critical flow velocity and stability maps of the pipe are obtained for various elastic foundation parameters, mass ratios of the pipe, and structural damping coefficients. Especially critical mass ratios, at which the transference of the eigenvalue branches related to flutter takes place, are precisely determined. Finally, the flutter configuration of the pipe at the critical flow velocities is drawn graphically at every twelfth period to define the order of the quasi-mode of flutter configuration.

Eigenvalue Branches and flutter Modes of Pipes on Elastic Foundations (탄성기초위에 놓인 파이프의 고유치 분기와 플러터 모드)

  • 류봉조;류시웅;김희중
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2003.11a
    • /
    • pp.486-491
    • /
    • 2003
  • The paper presents the relationship between the eigenvalue branches and the corresponding flutter modes of cantilevered pipes conveying fluid. The pipes are located on elastic foundations which can be regarded as a soil model. In this paper, elastic foundations are assumed as linear distributed translational springs. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The critical How velocity and stability maps of the pipe are investigated according to the variation of elastic foundation parameters, mass ratios of the pipe and internal damping Parameter. Also, the vibrational modes associated with flutter are shown.

  • PDF

Eigenvalue Branches and Flutter Modes of a Discontinuous Cantilevered Pipe Conveying Fluid (유동유체에 의한 불연속 외팔 파이프의 고유치 분기와 플러터 모드)

  • 류시웅;임경빈;류봉조
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.14 no.10
    • /
    • pp.1041-1047
    • /
    • 2004
  • This paper deals with the dynamic stability and vibration of a discontinuous cantilevered Pipe conveying fluid. The present model consists of two segments with different cross-sections. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The critical flow velocities and stability maps of the pipe are obtained by changing ratios of second area moment of inertia and mass ratios. Finally, the vibrational modes associated with flutter are shown graphically.

The Effect of a Tip Mass on Dynamic Stability of Pipes on Elastic Foundations (탄성기초 위에 놓인 파이프의 동적 안정성에 미치는 말단 질량의 영향)

  • 류봉조;김건희
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.14 no.11
    • /
    • pp.1115-1122
    • /
    • 2004
  • The paper discussed the effect of a tip mass on the stability of pipes on elastic foundations. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. With or without internal damping, the critical flow velocities of the pipes are investigated according to the variation of elastic foundation parameters and tip mass ratios. Also. the relationship between the eigenvalue branches and the corresponding flutter modes of the cantilevered pipes with a tip mass on the elastic foundations is fully investigated.

Study on the Stability of Cantilevered Pipe Conveying Fluid Subjected to Distributed Follower Force (분포종동력을 받는 외팔 송수관의 안정성에 관한 연구)

  • Kong, Chang-Duk;Park, Yo-Chang
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.33 no.4
    • /
    • pp.27-34
    • /
    • 2005
  • The paper discussed on the stability of cantilevered pipe conveying fluid subjected to distributed follower force. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The critical flow velocity as a function of the distributed follower force for the various mass ratio is determined. The flutter configurations of the pipes at the critical flow velocities are drawn graphically at every twelfth period to define the order of quasi-mode of flutter configuration The critical mass ratios, at which the transference of the eigenvalue branches related to flutter take place, are definitely determined. Also, the effect of damping on the stability of the system is considered.

Understanding of unsteady pressure fields on prisms based on covariance and spectral proper orthogonal decompositions

  • Hoa, Le Thai;Tamura, Yukio;Matsumoto, Masaru;Shirato, Hiromichi
    • Wind and Structures
    • /
    • v.16 no.5
    • /
    • pp.517-540
    • /
    • 2013
  • This paper presents applications of proper orthogonal decomposition in both the time and frequency domains based on both cross spectral matrix and covariance matrix branches to analyze multi-variate unsteady pressure fields on prisms and to study spanwise and chordwise pressure distribution. Furthermore, modification of proper orthogonal decomposition is applied to a rectangular spanwise coherence matrix in order to investigate the spanwise correlation and coherence of the unsteady pressure fields. The unsteady pressure fields have been directly measured in wind tunnel tests on some typical prisms with slenderness ratios B/D=1, B/D=1 with a splitter plate in the wake, and B/D=5. Significance and contribution of the first covariance mode associated with the first principal coordinates as well as those of the first spectral eigenvalue and associated spectral mode are clarified by synthesis of the unsteady pressure fields and identification of intrinsic events inside the unsteady pressure fields. Spanwise coherence of the unsteady pressure fields has been mapped the first time ever for better understanding of their intrinsic characteristics.