Effect of Fins on Vortex Shedding Noise Generated From a Circular Cylinder in Cross Flow

Hamakawa, Hiromitsu; Kouno, Yuji; Nishida, Eiichi

doi:10.1115/fedsm-icnmm2010-30290

Cited by 6 publications

(11 citation statements)

References 11 publications

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“…7 shows profiles of the stream-wise turbulence intensity for all fin pitches measured at the u'max point in the transverse direction. The locations of maximum turbulence intensity were near the wake of finned tube at X/De = 1.3-2.2 and were not shifted to the downstream side as in the results for a serrated finned tube (Hamakawa et al (2010)). The maximum turbulence intensities for s/D = 0.80 and 0.11 were about 19% lower than those for s/D = 0.27 and 0.16.…”

Section: Velocity Fluctuation In the Wake Of A Finned Tubesupporting

confidence: 57%

“…It is noteworthy that the vortex shedding phenomenon had a strong periodicity in the wake of the finned tube for small fin pitches, even though the velocity gradient might be weak in the separation shear layer. Measurements at different fin shapes showed similar features in Hamakawa et al (2010).…”

Section: Velocity Fluctuation In the Wake Of A Finned Tubesupporting

confidence: 52%

“…The characteristic length of the Strouhal number of the finned tube was used for the equivalent diameter of the finned tube, De (Mair, et al, 1975, Suzuki, et al, 1986, Hamakawa, et al, 2001, 2010 ( 3)where D is the tube diameter, Df is the fin diameter, s is the fin pitch, t is the fin thickness perpendicular to the spiral axis, U∞ is the freestream velocity, and ν is the kinematic viscosity. The aerodynamic sound in the far field from the test tube was measured at X = 0 mm, Y = 1000 mm, and Z = 0 mm using a microphone.…”

Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

“…The spectra of the sound pressure level (SPL) of the aerodynamic sound radiated from the test tubes were measured (Hamakawa et al (2010)). Fig.…”

Section: Aeolian Tone Radiated From a Finned Tubementioning

confidence: 99%

“…The spanwise correlation length of vortex shedding is the basic parameter needed to estimate the characteristics of sound generation by vortex shedding from a finned tube. Hamakawa et al (2010) observed that increasing the fin density decreases the vortex shedding noise radiated from a single serrated finned tube. Eid and Ziada (2011) showed that the introduction of fins to the cylinder might suppress the acoustic resonance.…”

Section: Introductionmentioning

confidence: 97%

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Aeolian tone radiated from a circular cylinder with solid spiral fin in cross flow

Hamakawa

Adachi

Matsuoka

et al. 2014

JFST

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Weaver, 1993, Ziada and Oengören, 1993). The vortex excitation has been shown to result from the formation of periodic vortices in the space between the tubes (Weaver, 1993, Ziada and Oengören, 1993). Recently, finned tubes have been used in heat recovery steam generator to enhance heat transfer. The fins are mounted spirally around a bare tube surface so as to simplify the production process. It is generally believed that vortex-induced vibration can be suppressed by mounting helical strakes around a bare tube (Blevins, 1986, Zdravkovich, 1981). Zdravkovich (1981) showed that helical strakes consisting of several fins acting as surface protrusions around a bare tube can also reduce vibration. However, acoustic resonance and vortex shedding phenomena still occur occasionally in the

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Section: Velocity Fluctuation In the Wake Of A Finned Tubesupporting

confidence: 57%

Section: Velocity Fluctuation In the Wake Of A Finned Tubesupporting

confidence: 52%

Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

“…The spectra of the sound pressure level (SPL) of the aerodynamic sound radiated from the test tubes were measured (Hamakawa et al (2010)). Fig.…”

Section: Aeolian Tone Radiated From a Finned Tubementioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Aeolian tone radiated from a circular cylinder with solid spiral fin in cross flow

Hamakawa

Adachi

Matsuoka

et al. 2014

JFST

Self Cite

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Effect of fin density and fin height on flow-induced vibration behavior of finned tube arrays subjected to water cross flow

Desai

Sonare

2023

MMMS

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PurposeThe prediction of critical velocity at instability threshold for shell and tube heat exchangers is important to avoid failure of tubes as a result of flow-induced vibrations due to water cross flow. The flow-induced vibration in finned tube heat exchangers is affected by various parameters such as fin height, fin pitch, fin material, tube array, pitch ratio, fin type, fluid velocity etc. In this paper, an experimental investigation of fluid elastic instability in shell and tube heat exchangers is carried out by subjecting normal square finned tube arrays of pitch ratio 1.79 to water cross flow.Design/methodology/approachThe five tube arrays, namely plain array, two finned tube arrays with 3 fpi and 9 fpi fin density, and two finned tube arrays with 3 mm and 6 mm fin height are tested in the experimental test setup with water flow loop and vibration measurement system. The research objective is to evaluate the effect of fin density and fin height on the instability threshold. The critical velocity at instability threshold is determined to characterize the fluid elastic instability behavior of different tube arrays. The vortex shedding behavior of the tube arrays is also studied by determining Strouhal number corresponding to the small peaks before fluid elastic instability.FindingsThe fluid elastic instability behavior of the tube arrays was found to be the function of fin tube parameters. The experimental results indicate that an increase in fin density and fin height results in delaying the instability threshold for finned tube arrays. It is also observed that critical velocity at instability is increased for finned tube arrays compared to plain tube arrays of the same pitch ratio. The design modifications in the outer box have resulted in further reduction in the natural frequency. This enabled to reach clear instability for all the five-tube arrays.Originality/valueThe research data add the value to the present body of knowledge by knowing the effect of fin height and fin density on the fluid elastic instability threshold of normal square finned tube arrays subjected to water cross flow.

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Fluid elastic instability and vortex induced vibration parameters in finned tube arrays with P/D ratio 1.79

Yadav¹,

Mohanty²

2021

WJE

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Purpose This paper aims to analyze the effect of fin geometry on mechanisms of flow induced vibration. Finned tube arrays are used in a heat exchanger to increase its efficiency. Therefore, it is necessary to investigate the effect of geometric parameters of the fin fluid elastic instability and vortex shedding. In this paper, the effect of fin height, fin density and tube pitch ratio for parallel triangular tube array on fluid elastic instability and vortex shedding is analyzed. Design/methodology/approach Experimental analysis was carried out on a parallel triangular finned tube array with a pitch ratio of 1.79 subjected to water crossflow. The experimentation aims to study fluid elastic instability and vortex-induced vibration mechanism responsible for flow induced vibration for finned tube array. A fully flexible finned tube array of the copper tube was used with its base diameter of 19.05 mm and thickness of 2 mm. Over the tube surface, crimped fins of height 6 mm and the same material are welded spirally with fin density 8.47 mm and 2.82 mm. Experimental analysis was carried out on a test setup developed for the same. The results obtained for the finned tube array were compared with those for the plain tube array with the same base tube diameter. Findings For parallel triangular tube array of copper material, test results show that critical velocity increases with an increase in fin pitch density for low pitch tube array. Before the occurrence of instability, the rate of growth in tube vibrations is high for plain tubes compared to that with fin tubes. The results based on Owen’s hypothesis show vortex shedding before the occurrence of fluid elastic instability. The effect of fin geometry on vortex-induced forces is analyzed. For the tube array pattern understudy, the values of Conner’s constant K for coarse fin-tube and fine fin tube array are obtained, respectively, 6.14 and 7.25. Originality/value This paper fulfills the need for research on the effect of fin geometry on fluid elastic instability and Vortex shedding on a tube array subjected to water cross flow when the pitch ratio is less than two, i.e. with a low pitch ratio.

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Effect of Fins on Vortex Shedding Noise Generated From a Circular Cylinder in Cross Flow

Cited by 6 publications

References 11 publications

Aeolian tone radiated from a circular cylinder with solid spiral fin in cross flow

Aeolian tone radiated from a circular cylinder with solid spiral fin in cross flow

Effect of fin density and fin height on flow-induced vibration behavior of finned tube arrays subjected to water cross flow

Fluid elastic instability and vortex induced vibration parameters in finned tube arrays with P/D ratio 1.79

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