Bending-torsional instability of a viscoelastic cantilevered pipe conveying pulsating fluid with an inclined terminal nozzle

Askarian, A. R ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1007/s12206-018-0603-0
  3. Publisher: Korean Society of Mechanical Engineers , 2018
  4. Abstract:
  5. In the present study, dynamic stability of a viscoelastic cantilevered pipe conveying fluid which fluctuates harmonically about a mean flow velocity is considered; while the fluid flow is exhausted through an inclined end nozzle. The Euler-Bernoulli beam theory is used to model the pipe and fluid flow effects are modelled as a distributed load along the pipe which contains the inertia, Coriolis, centrifugal and induced pulsating fluid flow forces. Moreover, the end nozzle is modelled as a follower force which couples bending vibrations with torsional ones. The extended Hamilton's principle and the Galerkin method are used to derive the bending-torsional equations of motion. The coupled equations of motion are solved using Runge-Kutta algorithm with adaptive time step and the instability boundary is determined using the Floquet theory. Numerical results present effects of some parameters such as fluid flow fluctuation, bending-to-torsional rigidity ratio, nozzle inclination angle, nozzle mass and viscoelastic material on the stability margin of the system and some conclusions are drawn. © 2018, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature
  6. Keywords:
  7. Bending-torsional instability ; Follower force ; Inclined nozzle ; Principal and combination parametric resonance ; Continuum mechanics ; Equations of motion ; Flow velocity ; Galerkin methods ; Nozzles ; Pulsatile flow ; Runge Kutta methods ; Stability ; Viscoelasticity ; Euler Bernoulli beam theory ; Follower forces ; Inclined nozzles ; Instability boundaries ; Parametric resonance ; Pipe conveying pulsating fluid ; Runge-Kutta algorithms ; Visco-elastic material ; Vibrations (mechanical)
  8. Source: Journal of Mechanical Science and Technology ; Volume 32, Issue 7 , July , 2018 , Pages 2999-3008 ; 1738494X (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s12206-018-0603-0