Vortex-induced vibration and flutter of a filament behind a circular cylinder

Mohd Furquan; Sanjay Mittal

doi:10.1007/s00162-023-00644-3

Vortex-induced vibration and flutter of a filament behind a circular cylinder

Mohd Furquan
, Sanjay Mittal^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

Abstract: Flow past a flexible filament, a two-dimensional splitter plate with negligible thickness, attached behind a circular cylinder is investigated. The Reynolds number based on the free-stream speed of incoming flow and diameter of the cylinder is Re = 100. At this Re , the flow for a rigid filament is steady. However, a flexible filament undergoes flow-induced vibration for a range of reduced speed, U^∗, defined as inverse of the first nondimensionalized natural frequency of the filament. Over the wide range of U^∗ considered in this work (U^∗≤ 240), it exhibits both flutter and vortex-induced vibration (VIV). Lock-in with various normal modes related to bending of the filament, each in a different regime of reduced speed, is observed during VIV. Interestingly, the fluid–structure system does not lock-in with the first normal mode of bending but with higher modes. The flow is steady for an extended range of reduced speed both before and after the lock-in with second mode. Two patterns of vortex shedding are observed. The 2P mode is associated with high-frequency vibration, while the 2S mode is observed during relatively low-frequency oscillation. A symmetry-breaking pitchfork bifurcation leads to static deflection of the filament during the first steady regime. The filament exhibits flutter response, at large reduced speed, with relatively low amplitude and frequency. No vortex shedding is observed during flutter. The fluid forces that cause flutter arise from asymmetry across the two sides of the filament in the zones of recirculation downstream of the cylinder. Comparison of the space-time patterns of energy transfer at the fluid–filament interface for flutter and vortex-induced vibration reveals that the energy transfer is much smaller during flutter compared to VIV. The point of maximum energy transfer is located close to the root of the filament in case of flutter, while it is near the tip during VIV. Graphic abstract: [Figure not available: see fulltext.].

Original language	English
Pages (from-to)	305-318
Number of pages	14
Journal	Theoretical and Computational Fluid Dynamics
Volume	37
Issue number	3
DOIs	https://doi.org/10.1007/s00162-023-00644-3
State	Published - Jun 2023
Externally published	Yes

Bibliographical note

Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Keywords

Fluid–structure interaction
Flutter
Laminar flow
VIV

ASJC Scopus subject areas

Computational Mechanics
Condensed Matter Physics
General Engineering
Fluid Flow and Transfer Processes

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10.1007/s00162-023-00644-3

Cite this

@article{f7df35b8e4a649a295539f24e84ae156,

title = "Vortex-induced vibration and flutter of a filament behind a circular cylinder",

abstract = "Abstract: Flow past a flexible filament, a two-dimensional splitter plate with negligible thickness, attached behind a circular cylinder is investigated. The Reynolds number based on the free-stream speed of incoming flow and diameter of the cylinder is Re = 100. At this Re , the flow for a rigid filament is steady. However, a flexible filament undergoes flow-induced vibration for a range of reduced speed, U∗, defined as inverse of the first nondimensionalized natural frequency of the filament. Over the wide range of U∗ considered in this work (U∗≤ 240), it exhibits both flutter and vortex-induced vibration (VIV). Lock-in with various normal modes related to bending of the filament, each in a different regime of reduced speed, is observed during VIV. Interestingly, the fluid–structure system does not lock-in with the first normal mode of bending but with higher modes. The flow is steady for an extended range of reduced speed both before and after the lock-in with second mode. Two patterns of vortex shedding are observed. The 2P mode is associated with high-frequency vibration, while the 2S mode is observed during relatively low-frequency oscillation. A symmetry-breaking pitchfork bifurcation leads to static deflection of the filament during the first steady regime. The filament exhibits flutter response, at large reduced speed, with relatively low amplitude and frequency. No vortex shedding is observed during flutter. The fluid forces that cause flutter arise from asymmetry across the two sides of the filament in the zones of recirculation downstream of the cylinder. Comparison of the space-time patterns of energy transfer at the fluid–filament interface for flutter and vortex-induced vibration reveals that the energy transfer is much smaller during flutter compared to VIV. The point of maximum energy transfer is located close to the root of the filament in case of flutter, while it is near the tip during VIV. Graphic abstract: [Figure not available: see fulltext.].",

keywords = "Fluid–structure interaction, Flutter, Laminar flow, VIV",

author = "Mohd Furquan and Sanjay Mittal",

note = "Publisher Copyright: {\textcopyright} 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.",

year = "2023",

month = jun,

doi = "10.1007/s00162-023-00644-3",

language = "English",

volume = "37",

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TY - JOUR

T1 - Vortex-induced vibration and flutter of a filament behind a circular cylinder

AU - Furquan, Mohd

AU - Mittal, Sanjay

PY - 2023/6

Y1 - 2023/6

N2 - Abstract: Flow past a flexible filament, a two-dimensional splitter plate with negligible thickness, attached behind a circular cylinder is investigated. The Reynolds number based on the free-stream speed of incoming flow and diameter of the cylinder is Re = 100. At this Re , the flow for a rigid filament is steady. However, a flexible filament undergoes flow-induced vibration for a range of reduced speed, U∗, defined as inverse of the first nondimensionalized natural frequency of the filament. Over the wide range of U∗ considered in this work (U∗≤ 240), it exhibits both flutter and vortex-induced vibration (VIV). Lock-in with various normal modes related to bending of the filament, each in a different regime of reduced speed, is observed during VIV. Interestingly, the fluid–structure system does not lock-in with the first normal mode of bending but with higher modes. The flow is steady for an extended range of reduced speed both before and after the lock-in with second mode. Two patterns of vortex shedding are observed. The 2P mode is associated with high-frequency vibration, while the 2S mode is observed during relatively low-frequency oscillation. A symmetry-breaking pitchfork bifurcation leads to static deflection of the filament during the first steady regime. The filament exhibits flutter response, at large reduced speed, with relatively low amplitude and frequency. No vortex shedding is observed during flutter. The fluid forces that cause flutter arise from asymmetry across the two sides of the filament in the zones of recirculation downstream of the cylinder. Comparison of the space-time patterns of energy transfer at the fluid–filament interface for flutter and vortex-induced vibration reveals that the energy transfer is much smaller during flutter compared to VIV. The point of maximum energy transfer is located close to the root of the filament in case of flutter, while it is near the tip during VIV. Graphic abstract: [Figure not available: see fulltext.].

AB - Abstract: Flow past a flexible filament, a two-dimensional splitter plate with negligible thickness, attached behind a circular cylinder is investigated. The Reynolds number based on the free-stream speed of incoming flow and diameter of the cylinder is Re = 100. At this Re , the flow for a rigid filament is steady. However, a flexible filament undergoes flow-induced vibration for a range of reduced speed, U∗, defined as inverse of the first nondimensionalized natural frequency of the filament. Over the wide range of U∗ considered in this work (U∗≤ 240), it exhibits both flutter and vortex-induced vibration (VIV). Lock-in with various normal modes related to bending of the filament, each in a different regime of reduced speed, is observed during VIV. Interestingly, the fluid–structure system does not lock-in with the first normal mode of bending but with higher modes. The flow is steady for an extended range of reduced speed both before and after the lock-in with second mode. Two patterns of vortex shedding are observed. The 2P mode is associated with high-frequency vibration, while the 2S mode is observed during relatively low-frequency oscillation. A symmetry-breaking pitchfork bifurcation leads to static deflection of the filament during the first steady regime. The filament exhibits flutter response, at large reduced speed, with relatively low amplitude and frequency. No vortex shedding is observed during flutter. The fluid forces that cause flutter arise from asymmetry across the two sides of the filament in the zones of recirculation downstream of the cylinder. Comparison of the space-time patterns of energy transfer at the fluid–filament interface for flutter and vortex-induced vibration reveals that the energy transfer is much smaller during flutter compared to VIV. The point of maximum energy transfer is located close to the root of the filament in case of flutter, while it is near the tip during VIV. Graphic abstract: [Figure not available: see fulltext.].

KW - Fluid–structure interaction

KW - Flutter

KW - Laminar flow

KW - VIV

UR - https://www.scopus.com/pages/publications/85149860639

U2 - 10.1007/s00162-023-00644-3

DO - 10.1007/s00162-023-00644-3

M3 - Article

AN - SCOPUS:85149860639

SN - 0935-4964

VL - 37

SP - 305

EP - 318

JO - Theoretical and Computational Fluid Dynamics

JF - Theoretical and Computational Fluid Dynamics

IS - 3

ER -

Vortex-induced vibration and flutter of a filament behind a circular cylinder

Abstract

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Keywords

ASJC Scopus subject areas

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