Review of sound induced by vortex shedding from cylinders

Blevins, Robert D.

doi:10.1016/0022-460x(84)90191-3

Cited by 80 publications

(44 citation statements)

References 44 publications

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“…The Aeolian tone from the circular cylinder has been studied by many researchers, which is summarized in review papers [1] [2]. These studies are concerned with the aerodynamic characteristics of the circular cylinder in a uniform flow, which is closely related to the generation mechanism of Aeolian tone.…”

Section: Introductionmentioning

confidence: 99%

Aeolian Tone from a Semi-Circular Cylinder in a Stream

Yamagata

Saito

Fujisawa

2016

JFCMV

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Aeolian tone from a semi-circular cylinder in a uniform flow is studied experimentally for various angles of attack. It is found that the peak sound spectrum of the Aeolian tone from the semi-circular cylinder is smaller than that from the circular cylinder and the lowest sound is observed around the zero angle of attack. This is due to the reduction in the fluctuating lift force on the semi-circular cylinder compared to that of the circular cylinder. This result suggests the validity of the analogy between the sound pressure level and the fluctuating lift force on a semi-circular cylinder in a stream. The flow visualization study also supports these results.

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Section: Introductionmentioning

confidence: 99%

Aeolian Tone from a Semi-Circular Cylinder in a Stream

Yamagata

Saito

Fujisawa

2016

JFCMV

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“…Investigations on sound generated from the flow around cylinders have a long history that goes back to the first observations of aeolian tones [1,2,3,4]. The major mechanism responsible for this sound generation is the intrinsic hydrodynamic instability of the wake downstream from the cylinder that, above a certain Reynolds number, leads to a periodic vortex shedding.…”

Section: Introductionmentioning

confidence: 99%

Vortex shedding noise of a cylinder with hairy flaps

Kamps

Geyer

Sarradj

et al. 2017

Journal of Sound and Vibration

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThis study describes the modification of acoustic noise emitted from cylinders in a stationary subsonic flow for a cylinder equipped with flexible hairy flaps at the aft part as a passive way to manipulate the flow and acoustics. The study was motivated by the results from previous water tunnel measurements, which demonstrated that hairy flaps can modify the shedding cycle behind the cylinder and can reduce the wake deficit. In the present study, wind tunnel experiments were conducted on such a modified cylinder and the results were compared to the reference case of a plain cylinder. The acoustic spectrum was measured using two microphones while simultaneously recording the flap motion. To further examine the flow structures in the downstream vicinity of the cylinder, constant temperature anemometry measurements as well as flow visualizations were also performed. The results show that, above a certain Reynolds number, the hairy flaps lead to a jump in the vortex shedding frequency. This phenomenon is similarly observed in the water flow experiments as a jump in the non-dimensional Strouhal number that is related to the change of the shedding cycle. This jump appears to be coupled to a resonant excitation of the flaps and a considerable increase of the flapping amplitude. The specific Reynolds number at which the jump Email addresses: Laura.Kamps@imfd.tu-freiberg.de (Laura Kamps), Thomas.Geyer@b-tu.de (Thomas F. Geyer) Preprint submitted to Journal of Sound and Vibration October 11, 2016 occurs is higher in the present case, which is attributed to the lower added mass in air as compared with the one in water. The flow visualizations confirmed that such action of the flaps lead to a more slender elongated shape of the time-averaged separation bubble. In addition, the hairy flaps induce a noticeable reduction of the tonal noise as well as broadband noise as long as the flaps do not touch each other.

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“…In the cases when a frequency coincidence was predicted for any other compressor, the inlet pressure was found to be less than 30 bar, agreeing well with the present observation that vibration did not occur when the inlet pressure was reduced below about 30 bar. This latter feature can be explained by the fact that at lower pressures, the sound power generated by vortex shedding is lower (Blevins 1984) and sound absorption by the #owing gas is higher (Kinsler et al 1999). …”

Section: Confirmation Of the Excitation Mechanismmentioning

confidence: 95%