<i>Sound and Sources of Sound</i>

Dowling, AP; Williams, J. E. Ffowcs; Wright, William G.

doi:10.1119/1.14260

Cited by 102 publications

(79 citation statements)

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“…The effect of convective amplification was removed using the theoretical factor (1 − M cos(φ)) 4 [32], where φ is the angle between the observer position and the flow direction, as shown in Eq. (2).…”

Section: Shear Layer and Convective Amplificationmentioning

confidence: 99%

Experimental study of the aerodynamic noise radiated by cylinders with different cross-sections and yaw angles

Iglesias

Thompson

Smith

2016

Journal of Sound and Vibration

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Vortex shedding from cylinders has been extensively studied due to its occurrence in many engineering fields. Many experimental studies reported in the literature focus on the aerodynamics of the vortex shedding process but the literature about the radiated noise is more scarce. The aim of the work presented here is to extend the available noise data. Aero-acoustic wind tunnel tests were carried out using cylinders with different cross-sections: circular, square, rectangular and elliptical. Flow speeds between 20 and 50 m/s were used, corresponding to Reynolds numbers in the range from 1.6 × 10 4 to 1.2 × 10 5 . The dependence of the noise on the yaw angle, flow speed, cross-sectional shape, angle of attack and radiation angle (directivity) is assessed. The results obtained are compared, where possible, with those found in the literature for similar cases. It is intended that the results can be used for the validation and calibration of numerical and empirical aerodynamic noise prediction models.

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Section: Shear Layer and Convective Amplificationmentioning

confidence: 99%

Experimental study of the aerodynamic noise radiated by cylinders with different cross-sections and yaw angles

Iglesias

Thompson

Smith

2016

Journal of Sound and Vibration

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“…This is caused by two effects. First, the ground reflection effect increases the sound radiation around 5.5 dB based on the calculations using the image method [22]. Second, there are more flow interactions for the case with the ground underneath, as discussed earlier, which increases the noise generation (about 1.5 dB contribution to the overall noise).…”

Section: Influence Of Ground On Sound Radiationmentioning

confidence: 98%

The effect of a moving ground on the flow and aerodynamic noise behaviour of a simplified high-speed train bogie

Zhu

Thompson

2016

International Journal of Rail Transportation

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Aeroacoustic sources around the train bogie area are particularly important but involve complex flow. In this study, a numerical investigation is presented of the effect of a moving ground on the flow and aeroacoustic noise behaviour of a train bogie. These make use of the delayed detached-eddy simulation combined with an acoustic analogy for noise prediction. First the flow around an isolated wheelset (1:5 scale) is calculated when it is in proximity to the ground and this is compared with wind-tunnel measurements to verify the simulation. Then the flow and aerodynamic noise behaviour of a simplified high-speed train bogie at scale 1:10 with and without the ground underneath are studied numerically. It is found that a highly turbulent flow is generated within the bogie cavity and the ground increases the noise levels by 6-8 dB due to a combination of acoustic reflection from the ground and modifications to the flow.

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“…However in the theoretical simulation for acoustic measurements, the discrete Fourier transform (DFT) is applied and thus Λ 1 (ω) actually means the frequency-dependent source power [22]. In this case, the equivalent source strength a 1 (ω) required by the simulation program SIMSRC can not be derived directly from Λ 1 (ω) in Eq.…”

Section: Equivalent Source Strengthsmentioning

confidence: 99%

“…The acoustic frequency spectrum for an ideal monopole in a medium without flow can be expressed as [22]:p…”

Section: Acoustic Field Of a Dipolementioning

confidence: 99%

Measurement and simulation of surface roughness noise using phased microphone arrays

Liu

Dowling

Shin

2008

Journal of Sound and Vibration

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Sound and Sources of Sound

Cited by 102 publications

References 0 publications

Experimental study of the aerodynamic noise radiated by cylinders with different cross-sections and yaw angles

Experimental study of the aerodynamic noise radiated by cylinders with different cross-sections and yaw angles

The effect of a moving ground on the flow and aerodynamic noise behaviour of a simplified high-speed train bogie

Measurement and simulation of surface roughness noise using phased microphone arrays

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