Study of a New Highly Absorptive Acoustic Element

Auriemma, Finizia

doi:10.1007/s40857-017-0087-6

Cited by 14 publications

(4 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In classical applications, a slit can be created by removing material from the plate [2,3,9]. Slits can also be generated by mating two slotted layers [6,10]. Alternative designs of MSAs have been reported in the literature [2,3,6,11,12].…”

Section: Introductionmentioning

confidence: 99%

Effect of slit length on linear and non-linear acoustic transfer impedance of a micro-slit plate

et al. 2022

View full text Add to dashboard Cite

The effect of the slit length on the acoustic transfer impedance of micro-slit plates (MSPs) is investigated in the linear and non-linear regime for a specific slit geometry. This geometry is inspired by slits obtained by cutting and bending the plate. MSPs are plates with arrays of slit-shaped perforations, with the width of the order of the acoustic viscous boundary layer thickness. Impedance tube measurements on two accurately manufactured plates are compared to numerical solution of the Linearized Navier-Stokes equations and to analytical limits. The impedance of the plate is obtained by the impedance of a single slit divided by the plate porosity. The resistance of a slit is independent on the slit length and on the plate porosity. In the linear regime the resistance is accurately predicted by a two-dimensional numerical model. In the non-linear regime, the resistance is strongly dependent on the amplitude of the acoustic waves. The inertance of the slit is weakly dependent on the slit length and on the plate porosity, for low and moderate amplitudes. For high amplitudes, a complicated amplitude dependency of the inertia of short slits is found. One expects that most of the conclusions obtained can be generalised to other slit geometries.

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of slit length on linear and non-linear acoustic transfer impedance of a micro-slit plate

et al. 2022

View full text Add to dashboard Cite

show abstract

“…δκ and δν represent a measure of the length scale for the oscillatory thermal and viscous diffusion, i.e. the distance from the solid wall where heat and momentum can diffuse laterally during the time T/π, where T is the period of the acoustic oscillation [12,13]. At longer distances, the fluid responds adiabatically to the acoustic perturbation, whilst in the very proximity of the walls the response is isothermal.…”

Section: Small Scale Standing-wave Taementioning

confidence: 99%

Use of Selective Laser Melting for Manufacturing the Porous Stack of a Thermoacoustic Engine

Auriemma

Holovenko

2019

KEM

Self Cite

View full text Add to dashboard Cite

In this study the authors investigate the possibility of using Selective Laser Melting (SLM) to manufacture the porous element (stack) of a thermoacoustic engine. Two stacks, provided with different internal geometries but with the same hydraulic radii, have been produced: one with parallel plates and one with a new, oblique pin array configuration. The pin array stacks provide smaller amount of viscous losses during the thermal to acoustic power conversion when working fluids with Pr < 1, e.g. air. Furthermore, the oblique configuration is designed to reduce the heat transmission from the hot to the cold surface of the stack, thus to achieve more easily the temperature gradient for the onset of the thermoacoustic phenomenon. In general, the pin array configurations are difficult to manufacture with conventional technologies. However, the SLM provides precise control of the features of the printed object, thus allowing to objectively compare the behavior of the two stacks. To this aim, the temperature gradient between the hot and cold faces of the stacks and the corresponding sound pressure levels measured at 15 cm from the open end of the engine are measured and compared.

show abstract

“…In recent decades, various studies have investigated the nonlinear vibration and absorption, insulation, and propagation of sound (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14]). However, most of these works have focused on only a single research area (e.g., nonlinear vibration or acoustics).…”

Section: Introductionmentioning

confidence: 99%

Chaotic Vibration and Perforation Effects on the Sound Absorption of a Nonlinear Curved Panel Absorber

Lee

2023

Mathematics

View full text Add to dashboard Cite

This study is the first to investigate the effect of chaotic vibration on the sound absorption of a curved perforated panel. Previous studies on the effect of nonlinear vibration on the sound absorption of a panel absorber have focused on periodic responses only. In this study, a sound absorption formula was derived by considering the panel impedance and perforation impedance. The numerical integration method was adopted to generate various chaotic vibrational responses, which were used to compute the corresponding sound absorptions. Several interesting findings that have never been observed in any previous studies on acoustic absorption were derived. First, in the chaotic and highly nonlinear cases, as the excitation frequency increased, the corresponding response frequencies decreased. This was opposite to the typical trend in linear cases, in which higher excitation frequencies corresponded to higher response frequencies. Second, in chaotic cases, absorption mainly occurred due to panel vibration effects. This is also in stark contrast to the findings of studies on perforated vibrating panels, in which the absorption effect mainly originates from perforations. Additionally, the absorption bandwidths are much wider and can shift to higher frequencies; however, the peak absorption coefficients were approximately 20% lower than in the case of the perforation effect only. Third, in the quasi-chaotic case, the absorption curve in the case of the perforation effect plus the vibration effect was between the absorption curves of the perforation effect only and the perforation effect plus the vibration effect.

show abstract

Study of a New Highly Absorptive Acoustic Element

Cited by 14 publications

References 14 publications

Effect of slit length on linear and non-linear acoustic transfer impedance of a micro-slit plate

Effect of slit length on linear and non-linear acoustic transfer impedance of a micro-slit plate

Use of Selective Laser Melting for Manufacturing the Porous Stack of a Thermoacoustic Engine

Chaotic Vibration and Perforation Effects on the Sound Absorption of a Nonlinear Curved Panel Absorber

Contact Info

Product

Resources

About