### Abstract

Numerical simulations based on the ALE finite element method are carried out to examine the aerodynamics of an oscillating circular cylinder when the separated shear flows around the cylinder are stimulated by periodic jet excitation with a shear layer instability frequency. The excitation is applied to the flows from two points on the cylinder surface. The numerical results showed that the excitation with a shear layer instability frequency can reduce the negative damping and thereby stabilize the aerodynamics of the oscillating cylinder. The change of the lift phase seems important in stabilizing the cylinder aerodynamics. The change of lift phase is caused by the merger of the vortices induced by the periodic excitation with a shear layer instability frequency, and the vortex merging comes from the high growth rate, the rapid increase of wave number and decrease of phase velocity for the periodic excitation in the separated shear flows.

Original language | English |
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Pages (from-to) | 141-150 |

Number of pages | 10 |

Journal | Wind and Structures, An International Journal |

Volume | 5 |

Issue number | 2-4 |

Publication status | Published - Mar 2002 |

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### Keywords

- Aerodynamic instability
- ALE
- Circular cylinder
- Finite element method
- Periodic excitation
- Separated shear layer
- Shear layer instability
- Vortex-induced vibration

### ASJC Scopus subject areas

- Renewable Energy, Sustainability and the Environment
- Civil and Structural Engineering
- Computational Mechanics
- Mechanics of Materials
- Building and Construction

### Cite this

*Wind and Structures, An International Journal*,

*5*(2-4), 141-150.

**Numerical study of the effect of periodic jet excitation on cylinder aerodynamic instability.** / Hiejima, Shinji; Nomura, T.

Research output: Contribution to journal › Article

*Wind and Structures, An International Journal*, vol. 5, no. 2-4, pp. 141-150.

}

TY - JOUR

T1 - Numerical study of the effect of periodic jet excitation on cylinder aerodynamic instability

AU - Hiejima, Shinji

AU - Nomura, T.

PY - 2002/3

Y1 - 2002/3

N2 - Numerical simulations based on the ALE finite element method are carried out to examine the aerodynamics of an oscillating circular cylinder when the separated shear flows around the cylinder are stimulated by periodic jet excitation with a shear layer instability frequency. The excitation is applied to the flows from two points on the cylinder surface. The numerical results showed that the excitation with a shear layer instability frequency can reduce the negative damping and thereby stabilize the aerodynamics of the oscillating cylinder. The change of the lift phase seems important in stabilizing the cylinder aerodynamics. The change of lift phase is caused by the merger of the vortices induced by the periodic excitation with a shear layer instability frequency, and the vortex merging comes from the high growth rate, the rapid increase of wave number and decrease of phase velocity for the periodic excitation in the separated shear flows.

AB - Numerical simulations based on the ALE finite element method are carried out to examine the aerodynamics of an oscillating circular cylinder when the separated shear flows around the cylinder are stimulated by periodic jet excitation with a shear layer instability frequency. The excitation is applied to the flows from two points on the cylinder surface. The numerical results showed that the excitation with a shear layer instability frequency can reduce the negative damping and thereby stabilize the aerodynamics of the oscillating cylinder. The change of the lift phase seems important in stabilizing the cylinder aerodynamics. The change of lift phase is caused by the merger of the vortices induced by the periodic excitation with a shear layer instability frequency, and the vortex merging comes from the high growth rate, the rapid increase of wave number and decrease of phase velocity for the periodic excitation in the separated shear flows.

KW - Aerodynamic instability

KW - ALE

KW - Circular cylinder

KW - Finite element method

KW - Periodic excitation

KW - Separated shear layer

KW - Shear layer instability

KW - Vortex-induced vibration

UR - http://www.scopus.com/inward/record.url?scp=0036504131&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036504131&partnerID=8YFLogxK

M3 - Article

VL - 5

SP - 141

EP - 150

JO - Wind and Structures, An International Journal

JF - Wind and Structures, An International Journal

SN - 1226-6116

IS - 2-4

ER -