Two Types of Frequency-Domain Acoustic-Velocity Formulations for Rotating Thickness and Loading Sources

Mao, Yijun; Zhang, Qunlin; Xu, Chunxiao; Qi, Datong

doi:10.2514/1.j053230

Cited by 18 publications

(12 citation statements)

References 30 publications

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“…Noise generated by aircraft, fans and others has great influence on the aeroacoustic research (Polacsek et al 1999; Greenwood and Schmitz 2014; Kingan 2014; Johnson 1980; Mao et al 2015). In these applications, the direct sound field and scattering effect are always considered to assess the acoustic impact of sound sources (Mouille 1970, 1986; Lowson 2015).…”

Section: Introductionmentioning

confidence: 99%

Numerical method to compute acoustic scattering effect of a moving source

Song

Huang

et al. 2016

SpringerPlus

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In this paper, the aerodynamic characteristic of a ducted tail rotor in hover has been numerically studied using CFD method. An analytical time domain formulation based on Ffowcs Williams–Hawkings (FW–H) equation is derived for the prediction of the acoustic velocity field and used as Neumann boundary condition on a rigid scattering surface. In order to predict the aerodynamic noise, a hybrid method combing computational aeroacoustics with an acoustic thin-body boundary element method has been proposed. The aerodynamic results and the calculated sound pressure levels (SPLs) are compared with the known method for validation. Simulation results show that the duct can change the value of SPLs and the sound directivity. Compared with the isolate tail rotor, the SPLs of the ducted tail rotor are smaller at certain azimuth.

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Section: Introductionmentioning

confidence: 99%

Numerical method to compute acoustic scattering effect of a moving source

Song

Huang

et al. 2016

SpringerPlus

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“…To obtain acoustic pressure gradient formulations, the gradient operation is performed to Eqs. (18)(19)(20), yielding…”

Section: A Convective Fw-h Equation and Its Time-domain Solutionmentioning

confidence: 99%

“…When solving acoustic scattering problems, the key aspect is obtaining the acoustic velocity on the scattering surface to serve as the boundary condition. Recently, Ghorbaniasl et al [19] suggested the analytic formulations V1 and V1A for calculating the acoustic velocity directly in the time domain, whereas the counterpart in the frequency domain was proposed by Mao et al [20]. Given that the direct derivation of the acoustic velocity involves heavy algebraic manipulations, the acoustic pressure gradient can also be used as the boundary condition because it is related to the acoustic velocity through the acoustic velocity potential [21].…”

mentioning

confidence: 99%

Analytic Time-Domain Formulation for Acoustic Pressure Gradient Prediction in a Moving Medium

Wang

Zhang

2017

AIAA Journal

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This paper presents an analytic time-domain formulation for acoustic pressure gradient prediction in a moving medium, which has significant application potential in evaluating the acoustic scattering boundary condition. Based on the convective Ffowcs Williams-Hawkings equation, a semianalytic time-domain acoustic pressure gradient formulation with a form involving the observer time differentiation outside the integrals is first developed, and then the desired analytic time-domain acoustic pressure gradient formulation is derived. Because the derived formulations are performed directly in the time domain, they are particularly applicable to the moving observer case. Simulation results for a stationary monopole source, a stationary dipole source, as well as a rotating monopole source in a moving medium demonstrate the effectiveness and accuracy of the proposed formulations for both stationary and moving sources with moving observers. Nomenclature

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“…Ghorbaniasl et al [19] developed time-domain acoustic velocity formulations for monopole and dipole sources in arbitrary motion, and Mao et al [20] deduced frequency-domain acoustic velocity formulations for rotating monopole and dipole sources with a constant angular speed. After that, acoustic intensity fields around sources [21] and scattering boundaries [22,23] were visualized to illustrate the propagation of acoustic energy.…”

Section: Introductionmentioning

confidence: 99%

Two Types of Frequency-Domain Acoustic-Velocity Formulations for Rotating Thickness and Loading Sources

Cited by 18 publications

References 30 publications

Numerical method to compute acoustic scattering effect of a moving source

Numerical method to compute acoustic scattering effect of a moving source

Analytic Time-Domain Formulation for Acoustic Pressure Gradient Prediction in a Moving Medium

Vector Aeroacoustics for Uniform Mean Flow: Acoustic Velocity and Vortical Velocity

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