Forward projection of transient sound pressure fields radiated by impacted plates using numerical Laplace transform

Blais, Jean-François; Ross, Annie

doi:10.1121/1.3097765

Cited by 26 publications

(8 citation statements)

References 23 publications

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“…Moreover, Q k (λ) and Z k (λ) should be defined in the interval [0, 2τ]. For sufficient accuracy, the suggested value of "λt" is given with the appropriate sign by [29]…”

Section: Vibration Suppressionmentioning

confidence: 99%

Sound Radiation Mitigation of Geometrically Nonlinear Plates Subjected to Subsonic Airflow

Norouzi

Younesian

2021

Mathematical Problems in Engineering

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This paper gives a theoretical analysis to obtain and reduce the acoustic pressure generated from plates with geometric nonlinearities subjected to subsonic airflow and external excitation. von-Kármán assumptions are applied considering the nonlinear terms in strain-displacement relations. Airflow passing through the plate is considered as an incompressible, irrotational, and inviscid flow. Galerkin’s method is employed to acquire the governing equations of time-dependent coefficients. Multiple Time Scale Method (MTSM) is then used to obtain the response of the plate. Suppressing undesirable vibration is carried out using an optimal tuned mass damper (TMD) system and an analytical solution is proposed based on Laplace transform and Adomian Decomposition Method (ADM). The acoustic pressure received from the plate is calculated by solving the Rayleigh integral using Boundary Element Method (BEM). A parametric study is carried out, and the effects of the flow speed, the aspect ratio, the thickness of the plate, the material of the plate, the forcing frequency, and the effectiveness of the designed TMD system on the sound pressure are examined. According to the results, using the TMD system reduces the amplitudes of the plate vibrations and, consequently, reduces the acoustic pressure around the vibrating plate. In this study, the passive control strategy leads to a significant decrease in the sound pressure level (about 35%) in some airflow speeds. Results show good efficiency in the control strategy. It is also found that the acoustic pressure generated from steel plates is significantly larger than that generated from aluminum plates. Moreover, increasing the aspect ratio and the plate thickness reduces the acoustic pressure. On the other hand, the external excitations with lower frequencies and the airflows with higher densities can generate lower sound pressures around the plate.

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“…Moreover, Q k (λ) and Z k (λ) should be defined in the interval [0, 2τ]. For sufficient accuracy, the suggested value of "λt" is given with the appropriate sign by [29]…”

Section: Vibration Suppressionmentioning

confidence: 99%

Sound Radiation Mitigation of Geometrically Nonlinear Plates Subjected to Subsonic Airflow

Norouzi

Younesian

2021

Mathematical Problems in Engineering

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“…Extensions of NAH have been proposed to address such cases. [2][3][4][5][6][7][8] As standard NAH is usually computed for a single frequency and then devoted to stationary sources, "Time domain holography" 2 was proposed for non-stationary sources: it consists of repeating NAH procedure on each spectral line and then applying the inverse Fourier transform to reconstruct a time evolution of sound field by an inverse Fourier transform. The process is well-adapted to short periods of time with limited bandwidth.…”

Section: Introductionmentioning

confidence: 99%

Instantaneous Bayesian regularization applied to real-time near-field acoustic holography

Magueresse¹,

Thomas

Antoni³

et al. 2017

The Journal of the Acoustical Society of America

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Real-time near-field acoustic holography (RT-NAH) is used to recover non-stationary sound sources using a planar microphone array. Direct propagation is described by the convolution of the wavenumber spectrum of the source under study with a known impulse response. The deconvolution operation is achieved by a singular value decomposition of the propagator and Tikhonov regularization is performed to stabilize the solution. The inverse problem has an innate ill-posed characteristic, and the regularization process is the key factor in obtaining acceptable results. The purpose of this paper is to present the instantaneous regularization process applied to RT-NAH method. Bayesian estimation of the regularization parameter is introduced from prior knowledge of the problem. The computation of the regularization parameter is updated for each block of constant time interval allowing one to take into account the fluctuating properties of the sound field. The superiority of Bayesian regularization, compared to state-of-the art methods, is observed numerically and experimentally for reconstruction of non-stationary sources. RT-NAH is also enhanced to allow the reconstruction of long signals. Updating the regularization parameter accordingly to the fluctuations of the SNR is revealed to be a necessary effort to reconstruct highly non-stationary sources.

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“…[3][4][5] Several timedomain near-field acoustical holography (TNAH) methods have been developed in the last decades to study the transient sound radiation. [6][7][8] Thomas et al 9 proposed a real-time nearfield acoustic holography (RT-NAH) method to continuously reconstruct the non-stationary acoustic fields by applying a convolution between the instantaneous wavenumber spectrum and the inverse impulse response. Zhang et al 10 developed a time-domain plane wave superposition method (TD-PWSM) by replacing the two dimensional spatial fast Fourier transform with the direct discretization of double infinite integral in the wavenumber domain.…”

Section: Introductionmentioning

confidence: 99%

Modeling transient sound propagation over an absorbing plane by a half-space interpolated time-domain equivalent source method

Pan

Jiang

Zhang

et al. 2014

The Journal of the Acoustical Society of America

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A half-space interpolated time-domain equivalent source method (ITDESM) is proposed to model the transient sound propagation over an absorbing plane. In this approach, a closed-form transient half-space Green's function (i.e., the impulse response function in three-dimensional space) for a pure absorbing infinite plane is introduced to develop the half-space ITDESM formulation. Instead of the free transient Green's function employed in the conventional ITDESM, such Green's function contains the reflection effect of the absorbing plane. As a numerical example, reconstructing the transient pressure fields from two monopole sources is depicted, where both monopoles are located in front of an infinite plane with absorbing impedance. Simulation results indicate that the half-space ITDESM can reconstruct the half-space transient sound fields in both the space and time domains very well. The proposed method is also investigated by taking into account the measurement noise in the reconstruction process. An experiment of an impacted steel plate above a glass wool board is presented to illustrate the validity of the proposed method under actual conditions.

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Forward projection of transient sound pressure fields radiated by impacted plates using numerical Laplace transform

Cited by 26 publications

References 23 publications

Sound Radiation Mitigation of Geometrically Nonlinear Plates Subjected to Subsonic Airflow

Sound Radiation Mitigation of Geometrically Nonlinear Plates Subjected to Subsonic Airflow

Instantaneous Bayesian regularization applied to real-time near-field acoustic holography

Modeling transient sound propagation over an absorbing plane by a half-space interpolated time-domain equivalent source method

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