Experimental Investigation of the Generation Mechanism of Aerodynamic Noise. 2nd Report. On Correlation between Surface Pressure Fluctuation and Aerodynamic Sound Radiated from a Circular Cylinder.

明由, 飯田; 肇, 藤田; 千幸, 加藤; 俊夫, 大田黒

doi:10.1299/kikaib.62.4160

Cited by 5 publications

(3 citation statements)

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“…The fourth power slope is very clear for the data from Sueki et al [26] (⭑), which is also well consistent with that from Casalino & Jacob [6] (▼). The two other studies [24,25] (•, ◀) reported results for a single span at different velocities, leading to more dispersion, but they do not contradict the trend.…”

Section: Experimental Datamentioning

confidence: 85%

Influence of the Length of a Cylinder on its Aeolian Tone Level: Measurement and Modelling

Pinto¹,

Margnat²,

Noûs³

2021

14th WCCM-ECCOMAS Congress

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The tonal noise generated by the flow over elongated cylinders is measured using microphones in the anechoic wind tunnel BETI of Institut Pprime. The effect of the length to diameter ratio of the cylinder is assessed by varying the diameter from 6 mm to 20 mm within the constant width (750mm), open jet, test section. The velocity is varied from 10 to 40 m/s, leading to a Reynolds number range of about 4,000 -53,000. A proper normalization is needed to obtain a good collapse of experimental data from nearly 10 studies on the same evolution in 3 steps: for very short cylinders, the tone level does not depend on the length; for semi-long cylinders, it follows the fourth power of the length to diameter ratio; for very long cylinder, the length's influence vanishes in the form of a sound level asymptote. This sigmoidal evolution is noticed for both the circular section and the square section cylinders, and questions the classical modelling of the aeroacoustic process using compact, coherent segments of cylinder associated with a coherence length to account for spanwise phase loss. Literature data from numerical simulation or experiment using end-plates are included in the analysis too.

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Section: Experimental Datamentioning

confidence: 85%

Influence of the Length of a Cylinder on its Aeolian Tone Level: Measurement and Modelling

Pinto¹,

Margnat²,

Noûs³

2021

14th WCCM-ECCOMAS Congress

View full text Add to dashboard Cite

show abstract

“…Resolving this is a clear challenge for future studies. The relationship between the position r c by which the pressure fluctuation of a short-distance field can be disregarded now, and the minimum frequency f is given in 20log(2πfr c /a) >=10 dB (a is acoustic velocity) (Iida, 1996). Distance r c between the circular cylinder and the microphone becomes 188mm-211mm because the range of center-to-center spacing x between the circular cylinder and the microphone in this experiment is 5mm-95mm.…”

Section: The Relation Between Sound Source and Measurement Positionmentioning

confidence: 94%

Experimental Study of Internal Flow Noise Measurement by Use of a Suction Type Low Noise Wind Tunnel

Yokoi¹

2013

Wind Tunnel Designs and Their Diverse Engineering Applications

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“…Therefore, hydrodynamic pressure fluctuations are dominant on the side window glass. The magnitude of hydrodynamic pressure fluctuations produced by convection of Lighthill's noise sources is inversely proportional to the fourth power of distance in the acoustical near field (10) . On the other hand, there are another Lighthill's noise sources, which exist in the sideview mirror wake (see Fig.…”

Section: Noise Sources Distributed Around Sideview Mirrormentioning

confidence: 99%

Verification of Automobile Aerodynamic Noise Transmitted through Side Window Glass

Okutsu

Hamamoto

Yanagimoto

et al. 2013

JEE

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To research the mechanism of automobile aerodynamic noise which transmits to the inside of a cabin, the flow structure and sound field have been investigated by making experimental measurements at the wind tunnel and performing Computational Fluid Dynamics (CFD) based on the Lattice Boltzmann Method (LBM). The noise transmitted at a window glass on the front side is focused in this study. Pressure fluctuations on the side window glass contain both hydrodynamic pressure fluctuations induced by the flow field and acoustic pressure fluctuations propagated from noise sources. It was found by examining the experimental transmission loss that on the side window glass it is close to the random incidence mass law in the high frequency range. To verify the outside sound field, the wave number -frequency spectrum method was applied to computational results in the region behind and outside a sideview mirror. Hydrodynamic and acoustic fluctuations were researched in the wave number -frequency region. This result suggests that the sound field behind the mirror is not a directional sound field but a diffuse sound field.

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Experimental Investigation of the Generation Mechanism of Aerodynamic Noise. 2nd Report. On Correlation between Surface Pressure Fluctuation and Aerodynamic Sound Radiated from a Circular Cylinder.

Cited by 5 publications

References 0 publications

Influence of the Length of a Cylinder on its Aeolian Tone Level: Measurement and Modelling

Influence of the Length of a Cylinder on its Aeolian Tone Level: Measurement and Modelling

Experimental Study of Internal Flow Noise Measurement by Use of a Suction Type Low Noise Wind Tunnel

Verification of Automobile Aerodynamic Noise Transmitted through Side Window Glass

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