Whistling behavior of periodic systems: Corrugated pipes and multiple side branch system

Nakiboglu, G Günes; Belfroid, S.P.C.; Willems, J. F. H.; Hirschberg, Avraham

doi:10.1016/j.ijmecsci.2010.03.018

Cited by 33 publications

(58 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8,12 This implies that sound production is a local effect, which can be studied for a single cavity. Thus, one can try to describe the phenomenon by carrying out a numerical simulation of the flow within a single cavity instead of modeling the whole corrugated pipe.…”

Section: Numerical Methodologymentioning

confidence: 99%

“…The peak-whistling Strouhal number of a corrugated pipe is determined through a linear least square fit of consecutive excited acoustic modes. 8 The peak-whistling Strouhal number of the Hummer is determined to be St pÀw Wþr up ¼ 0:44, which is actually presented as the Strouhal number St Wþr up ¼ 0:44 in Fig. 7.…”

Section: (Sr Crmentioning

confidence: 99%

“…Since the increase in the velocity is large compared to the corresponding increase in the frequency within the same acoustic resonant mode there is a range of Strouhal numbers, where the whistling is observed rather than a fixed Strouhal number. 8,23,24 However, the response of the resonator has a maximum at the passive resonance frequency f p and therefore a maximum of the whistling amplitude at f ¼ f p . At this point the convection time of the vortices is close to a multiple of an oscillation period T plus a quarter ðm þ 1=4ÞT ¼ ðm þ 1=4Þ=f (m ¼ 1; 2; 3; :::).…”

Section: Whistling Frequencies and Strouhal Numbermentioning

confidence: 99%

“…6 A more extensive review of the literature on corrugated pipes is given in the earlier papers of the authors. 7,8 Physical modeling of corrugated pipes by means of simple source models placed along a tube has been proposed by Debut 9 and Goyder. 10 A Large eddy simulation has been attempted by Popescu and Johansen, 11 but results seem to be in contradiction with the experimental studies.…”

Section: Introductionmentioning

confidence: 99%

“…10 A Large eddy simulation has been attempted by Popescu and Johansen, 11 but results seem to be in contradiction with the experimental studies. 8,12,13 In the present paper the physical modeling of this instrument is discussed. In the next section, an overview of the basic principles is given.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

Nakiboglu

Rudenko

Hirschberg

2012

The Journal of the Acoustical Society of America

Self Cite

View full text Add to dashboard Cite

When one swings a short corrugated pipe segment around one's head, it produces a musically interesting whistling sound. As a musical toy it is called a "Hummer" and as a musical instrument, the "Voice of the Dragon." The fluid dynamics aspects of the instrument are addressed, corresponding to the sound generation mechanism. Velocity profile measurements reveal that the turbulent velocity profile developed in a corrugated pipe differs notably from the one of a smooth pipe. This velocity profile appears to have a crucial effect both on the non-dimensional whistling frequency (Strouhal number) and on the amplitude of the pressure fluctuations. Using a numerical model based on incompressible flow simulations and vortex sound theory, excellent predictions of the whistling Strouhal numbers are achieved. The model does not provide an accurate prediction of the amplitude. In the second part of the paper the sound radiation from a Hummer is discussed. The acoustic measurements obtained in a semi-anechoic chamber are compared with a theoretical radiation model. Globally the instrument behaves as a rotating (Leslie) horn. The effects of Doppler shift, wall reflections, bending of the tube, non-constant rotational speed on the observed frequency, and amplitude are discussed.

show abstract

Section: Numerical Methodologymentioning

confidence: 99%

Section: (Sr Crmentioning

confidence: 99%

Section: Whistling Frequencies and Strouhal Numbermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

Nakiboglu

Rudenko

Hirschberg

2012

The Journal of the Acoustical Society of America

Self Cite

View full text Add to dashboard Cite

show abstract

Introduction to Aeroacoustics and Self-Sustained Oscillations of Internal Flows

Hirschberg

2013

Noise Sources in Turbulent Shear Flows: Fundamentals and Applications

View full text Add to dashboard Cite

Mitigation of whistling in vertical corrugated pipes by liquid addition

2017

View full text Add to dashboard Cite

(FIVs) can occur, caused by an interaction between an acoustic pipe resonance and the unsteady shear layers spanning the corrugations. Under certain conditions, these FIVs result in the production of high-amplitude tonal noise (also known as whistling). This is not only inconvenient, but can lead to damage of equipment, failure of piping systems, and hazardous situations. This study focuses on whistling attenuation by liquid addition to vertical corrugated pipe flow, and the identification of the mechanisms behind this attenuation. For this purpose, a new approach is developed to identify the liquid accumulation within the cavities based on planar laser-induced-fluorescence (PLIF) measurements. These measurements are combined with acoustic measurements to identify the sound production from the corrugated pipes. Burstyn (1922) and Cermak (1922) were the first of many to study the sound production from single-phase corrugated pipe flow. Since then, many studies have been devoted to the phenomenon behind the whistling behavior, which are summarized in a review paper on corrugated pipe flow by Rajavel and Prasad (2013).Whistling in corrugated pipes originates from a fluidacoustic feedback. The free shear layers spanning the cavities in this kind of flows are intrinsically unstable and can act as a source of sound. Under certain conditions, discrete vortices can be shed in the cavity mouth. Vortex shedding in the shear layers exerts an unsteady force on the walls, causing a reaction force, which is associated with the sound generation (Curle 1955). This sound source is of a dipole nature due to the vortex-wall interactions (Howe 2003), and feeds an axial acoustic mode in the pipe when the shedding frequency is below the cut-off frequency of the pipe. The acoustic perturbation caused by this acoustic resonance is a source of instability in the shear layers over the corrugations, triggering vortex shedding and closing the feedback loop.Abstract When a corrugated pipe is subject to a dry gas flow, high amplitude sound can be produced (so-called 'whistling'). It was shown previously that liquid addition to corrugated pipe flow has the ability to reduce sound production. Small amounts of liquid are sufficient to mitigate whistling entirely. One of the mitigation mechanisms, cavity filling, is studied experimentally. Acoustic measurements are combined with a planar laser-induced fluorescence technique to measure the liquid accumulation in the cavities of a corrugated pipe. Using this technique, it is shown that the amount of filling of the cavities with liquid increases with increasing liquid injection rate and with reducing gas flow rate. The reduction in whistling amplitude caused by the liquid injection is closely related to the cavity filling. This indicates that the geometric alteration of the pipe wall, caused by the accumulation of liquid inside the cavities, is an important factor in the reduction in whistling amplitude.

show abstract

Whistling behavior of periodic systems: Corrugated pipes and multiple side branch system

Cited by 33 publications

References 27 publications

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

Introduction to Aeroacoustics and Self-Sustained Oscillations of Internal Flows

Mitigation of whistling in vertical corrugated pipes by liquid addition

Contact Info

Product

Resources

About