Role of the foot chamber in the sounding mechanism of a flue organ pipe

Tateishi, Shuhei; Iwagami, Sho; Tsutsumi, Genki; Kobayashi, Taizo; Takami, Toshihiro; Takahashi, Kin’ya

doi:10.1250/ast.40.29

Cited by 5 publications

(11 citation statements)

References 19 publications

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“…More specific adjustments, namely the height of the lower labium relative to the languid and the inner geometry of the foot hole, were investigated by Adachi et al [ 9 ]. A deep study on the whole foot model is also present in the literature, with important observations on the jet’s natural oscillation, its velocity profile, and some optimum conditions for a stronger and more stable edge tone [ 33 , 34 ]. Fischer et al proposed the simulation of the entire pipe as well as some surrounding areas, reproducing not only the motion of the jet but also the sound wave propagation from the mouth and its pressure level spectra [ 35 ].…”

Section: Sound Production In Organ Pipesmentioning

confidence: 99%

Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach

Bordoni,

Odya,

Kotus

et al. 2024

Sensors

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This work presents an approach that integrates the results of measuring, analyzing, and modeling air flow phenomena driven by pressurized air in a flue organ pipe. The investigation concerns a Bourdon organ pipe. Measurements are performed in an anechoic chamber using the Cartesian robot equipped with a 3D acoustic vector sensor (AVS) that acquires both acoustic pressure and air particle velocity. Also, a high-speed camera is employed to observe the jet coming out from the windway. For that purpose, the steam resulting from dry ice and hot water is used. A numerical simulation of the sounding mechanism of a pipe of the same geometry is based on measuring the pressure signal and the intensity field around the mouth employing an intensity probe and visualizing and observing the motion of the air jet, which represents the excitation mechanism of the system. The ParaVIEW software serves for the simulation and visualization of the air jet. Then, the results obtained from measurements and simulations are compared and discussed. Also, some future directions discussing the application of a machine-learning approach to the area of pipe organ air flow investigation are contained in the Conclusions section.

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Section: Sound Production In Organ Pipesmentioning

confidence: 99%

Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach

Bordoni,

Odya,

Kotus

et al. 2024

Sensors

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“…From those data we have calculated streamlines of the flow and produced movies showing the time dependence of the streamline patterns. Images showing the density and/or flow as derived from experiments (e.g., in [2,3,5,13]) or from simulations (e.g., [9,14,15,16,17,18]) have been presented by previous workers. However, essentially all of those images have been limited to two dimensions, in the x-y plane of Fig.…”

Section: Jet Dynamics In the Hysteresis Regionmentioning

confidence: 99%

Air Jet Dynamics in a Flue Instrument

Giordano,

Saenger

2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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In a flue instrument such as the recorder, an air jet undergoes an oscillatory motion with the jet directed alternately to either side of the labium. The dynamics of that oscillation, including the trajectory followed by the jet, depends on the jet speed, a parameter controlled by the blowing pressure. We describe new studies of how the jet oscillations depend on blowing pressure in a recorder. Small Pitot-tube-like pressure sensors are installed in close proximity to the labium tip of a soprano recorder, with two sensors above the tip and two below. The pressures at these four locations give the timeaveraged spatial profile of the air jet. This profile is observed to change as the blowing pressure is increased from low values, where the note C5 is produced, to high pressures where the note an octave higher, C6, is sounded. Additionally, it was found that different spatial profiles are found for C5 and C6 even when they are produced at the same blowing pressure. We have compared the experimentally measured jet profiles with the results of Navier-Stokes-based simulations of the same instrument geometry under the same blowing conditions, and find similar variations in the timeaveraged jet profiles. The simulations also give the timeresolved jet profiles, which provide further insight into this behavior.

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“…On the other hand, the influence of the foot geometry on the jet motion and acoustic oscillation has seemed to attract less attention, although as a related issue the effect of the vocal tract on the sound production of recorders was reported by several authors [3,4]. In the previous works [5,6], we found with two-dimensional (2D) numerical simulations that the foot acts as a Helmholtz resonator and the change of its resonance frequency affects the stability of the acoustic oscillation and the relative phase between the pressure oscillation in the pipe and that in the foot. Note that the 2D models well captured the basic properties experimentally observed for the recorder-like flue organ pipe [2,5].…”

Section: Introductionmentioning

confidence: 99%

Numerical study on a three-dimensional model of a flue organ pipe: relative phase between pipe and foot, and stability

Ikoga,

Onomata,

Tabata

et al. 2022

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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To clarify the role of the foot of flue organ pipes, we numerically studied a three-dimensional model with changing foot geometry by compressible LES. The foot acts as a Helmholtz resonator and influences the acoustic oscillation in the pipe. We found that the relative phase of oscillations between the pipe and foot changes depending on the geometry of the foot, and the change of the relative phase can be explained by the theory of forced harmonic oscillators: the pipe works as a force driving the foot. When the resonance frequency of the foot, f f , is smaller than the frequency of acoustic oscillation, f a , antiphase synchronization between the pressure oscillation in the pipe and that in the foot is observed, while synchronization is observed when the f f is larger than f a . If f f is nearly equal to f a , the pressure oscillation in the foot is delayed by π/2 to that in the pipe, and the amplitude of the acoustic oscillation is smaller than in other cases. The weak instability observed in this case seems to be caused by nonlinear interaction between the pipe and foot via the jet oscillation.

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Role of the foot chamber in the sounding mechanism of a flue organ pipe

Cited by 5 publications

References 19 publications

Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach

Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach

Air Jet Dynamics in a Flue Instrument

Numerical study on a three-dimensional model of a flue organ pipe: relative phase between pipe and foot, and stability

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