Dual-target-frequency-range stop-band acoustic metamaterial muffler: acoustic and CFD approach

Kheybari, Majid; Ebrahimi-Nejad, Salman

doi:10.1088/2631-8695/ac1989

Cited by 11 publications

(4 citation statements)

References 46 publications

(50 reference statements)

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“…Nevertheless, the insulation of low-frequency sound remains a challenge, especially when using a sub-wavelength-scale metamaterial [38,39]. Moreover, a high degree of ventilation is desired in several applications, such as in buildings, stations and factories [40,44].…”

Section: Sound Insulationmentioning

confidence: 99%

Acoustic metamaterials with zero-index behaviors and sound attenuation

Wu¹,

Ke²,

Zhang³

et al. 2022

J. Phys. D: Appl. Phys.

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The Helmholtz resonator suffers from needing to be excessively large to manipulate low-frequency sound waves and supports only monopolar resonance. To solve these problems, combing with space-coiling concept and multiunit lumped coupling concept, a new metamaterial is proposed, that exhibits an extraordinary acoustic response related to multiple resonant patterns in the low-frequency regime. At the upper and lower edges of the bandgap, acoustic wavefront reshaping is achieved. Considering the shift of the modulation frequency and the mismatched impedance, an alternative and simple strategy is presented to achieve acoustic cloaking. Furthermore, by flexibly varying the distances between the metamaterial plates and inserted obstacles, acoustic cloaking independent of the boundary conditions of the inserted obstacles is achieved. Finally, based on the negative acoustic response of the structure, acoustic barriers capable of air ventilation and sound attenuation simultaneously are achieved and verified by experimental results.

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Section: Sound Insulationmentioning

confidence: 99%

Acoustic metamaterials with zero-index behaviors and sound attenuation

Wu¹,

Ke²,

Zhang³

et al. 2022

J. Phys. D: Appl. Phys.

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“…A few researchers have utilized acoustic metamaterials to design baffled mufflers, which are very accurate, but highly expensive alternatives. Kheybari et al [20,21] proposed acoustic metamaterial baffles and examined the performance of designed baffles in lowering exhaust noise by studying the TL levels. Others also tried to tune stopbands of acoustic metamaterials in addition to improve TL characteristics, e.g., Ravanbod et al [22] investigated the effect of materials and geometrical parameters on stopband properties and the TL of a cross-like beam structure with re-entrant properties.…”

Section: Introductionmentioning

confidence: 99%

Porous liner coated inlet duct: a novel approach to attenuate automotive turbocharger inlet flow-induced sound propagation

et al. 2023

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This paper proposes utilizing a thin porous material coating liner on the inlet duct of the turbocharger compressor in order to absorb the incident excitation and hence, broadband reduction of the flow-induced sound wave propagation. To this end, first, a sound-absorbing inlet duct model is designed based on efficient structural parameters. Then, three different types of absorptive materials are used as coating liners to analyze the impact of varying material properties on the acoustic absorption performance of the system. Meanwhile, a sensitivity analysis is carried out to evaluate the influence of coating layer thickness on the system’s flow-induced sound insulation performance. The research involves applying a finite element approach to conducting acoustic pressure and poroacoustics studies over the desired frequency range of human hearing (1-20 kHz). In this regard, sound transmission loss (TL) and sound pressure level (SPL) are investigated for the models with and without liners. The results indicate that sound-absorbing materials can be employed to significantly diminish flow-induced sound levels in the turbocharger inlet duct. According to the results, absorptive liners would considerably increase the maximum TL and lessen the sharp drop in TL that appeared in the model without liners at around 4321Hz. In addition, the average TL has increased due to the replacement of valleys with peaks. The sensitivity analyses demonstrated that denser absorptive materials and larger liner thicknesses are associated with higher TL levels and better sound attenuation response. By adding 15 mm of rock wool liner to the designed inlet duct, the average TL and root mean square of TL were increased up to 98 and 32 dB, respectively. The proposed design procedure of this study unlocks a fundamental approach that can be practically applied to many promising fields, such as aerospace and automotive engineering.

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“…Two variables, k and ε, which stand for the kinetic energy and dissipation rate, respectively, are presented in the turbulent flow field. The turbulent viscosity is derived from the below equation [45]:…”

mentioning

confidence: 99%

“…The following quasi-experimental equations are solved by ANSYS Fluent to find the values of k and ε [45]:…”

mentioning

confidence: 99%

Organized Computational Measurement to Design a High-Performance Muffler

Saadabadi,

Samimi,

Hosseinlaghab

2023

Metrology

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Engine noise, as a source of sound pollution for humans and the environment, can be reduced by designing a high-performance muffler. This study presents a novel, organized design process of that muffler for the KTM390 engine as a case study. The acoustic simulation analysis is performed in COMSOL software and aerodynamic analysis is performed in ANSYS Fluent. The features of the muffler considered in this designing process are the overall length of the muffler, the presence of baffles and related parameters (baffle distance, baffle hole diameter, and baffle hole offset), and the effects of extended tubes. In order to evaluate the acoustic performance of the muffler, an objective function has been defined and measured on two frequency ranges, 75–300 Hz and 300–1500 Hz. For evaluating the aerodynamic performance of that, the amount of backpressure is analyzed to achieve a maximum of 3.3 kilopascals for this muffler. The selection of the appropriate parameters includes comparing the resulting transmission loss curves and quantitative evaluation of objective functions (for transmission loss) and backpressure. This organized design process (i.e., tree diagram) leads to an increase in the efficiency of designing mufflers (for example, 41.2% improvement on backpressure).

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Dual-target-frequency-range stop-band acoustic metamaterial muffler: acoustic and CFD approach

Cited by 11 publications

References 46 publications

Acoustic metamaterials with zero-index behaviors and sound attenuation

Acoustic metamaterials with zero-index behaviors and sound attenuation

Porous liner coated inlet duct: a novel approach to attenuate automotive turbocharger inlet flow-induced sound propagation

Organized Computational Measurement to Design a High-Performance Muffler

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