Demonstration of effective acoustic properties of different configurations of Helmholtz resonators

Jena, D.P.; Dandsena, J.; Jayakumari, V. G.

doi:10.1016/j.apacoust.2019.06.004

Cited by 44 publications

(20 citation statements)

References 26 publications

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“…Following the lumped-element model, the metamaterial's effective density is not influenced by the Helmholtz resonator and is assumed to be the density of water. Other studies [35] [33], while the blue markers and solid blue line correspond to our FEM results. The negative density and modulus regions are depicted by a colored background (blue ≡ B eff < 0, red ≡ ρ eff < 0, green ≡ B eff < 0 and ρ eff < 0).…”

Section: A Dispersion Band Diagramsupporting

confidence: 80%

Design and Fabrication of Negative-Refractive-Index Metamaterial Unit Cells for Near-Megahertz Enhanced Acoustic Transmission in Biomedical Ultrasound Applications

et al. 2021

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We present the design of negative-refractive-index acoustic metamaterials operating at near-megahertz frequencies, intended for the eventual aim of enabling enhanced acoustic transmission through highimpedance-contrast biological layers. Leveraging the concept of complementary acoustic metamaterials, the negative effective properties of the metamaterials are designed to match the magnitude of an ultrasound-blocking, high-impedance-contrast layer's properties. The negative properties are obtained using a linear array of unit cells containing Helmholtz resonators and membranes. Using finite-element and analytical models, we calculate the band structure and the effective modulus and density of the proposed negative metamaterials. Using the full three-dimensional model of the metamaterials, we then simulate the enhancement of ultrasound transmission, through layers with high-impedance contrast to water. For instance, we see an improvement from 80% transmission through a high-impedance layer alone to 98% transmission through the metamaterial-plus-high-impedance layer combination. Scaling arguments are provided to estimate the system dimensions needed to provide higher operational frequencies appropriate for imaging and high-intensity ultrasound applications. Finally, as a proof of feasibility, a preliminary experimental realization of the unit-cell structure, created using the nanofabrication approach, is presented and tested in the near-megahertz regime. These results provide a step toward metamaterial-enhanced devices for noninvasive biomedical ultrasonic imaging and therapy.

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Section: A Dispersion Band Diagramsupporting

confidence: 80%

Design and Fabrication of Negative-Refractive-Index Metamaterial Unit Cells for Near-Megahertz Enhanced Acoustic Transmission in Biomedical Ultrasound Applications

et al. 2021

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“…Resonator Helmholtz (HR) merupakan peristiwa resonansi yang terjadi pada dinding-kaku yang memiliki rongga dan memiliki ruang yang kecil kemudian di bagian tengah memiliki ruang yang lebih besar (Jena et al, 2019). Aplikasi HR telah digunakan untuk meredam kebisingan yang dihasilkan oleh elemen penginduksi di berbagai sistem struktural saluran, seperti ventilasi dan AC untuk gedung, sistem saluran otomatis dan mesin udara (Cai & Mak, 2018).…”

Section: Pendahuluanunclassified

Resonansi Helmholtz: Pegas dalam Botol

Dewi

Okimustava

2020

Berk. Fis. Indones. J. Ilm. Fis. Pembelajaran dan Apl.

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Penelitian ini bertujuan untuk menemukan nilai frekuensi akustik dari botol. Resonansi Helmholtz yang digunakan dalam penelitian ini adalah frekuensi Helmholtz pada botol kaca bekas sirup. Penelitian ini dilakukan dengan memanfaatkan sebuah botol yang memiliki leher untuk mengetahui nilai resonansi Helmholtz. Pengukuran resonansi Helmholtz menggunakan aplikasi dari android yaitu spectroid karena dapat mengukur besar frekuensi dan dB. Hasil yang diperoleh yaitu terjadi penurunan frekuensi pada variasi volume ke 2.1224955 m 3 . Berdasarkan data yang diperoleh sesuai dengan prinsip Helmholtz. Semakin besar volume udara maka akan semakin kecil frekuensinya. Sedangkan nilai dB akan kecil jika volume makin kecil.This is an open access article under the CC-BY-SA license

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“…The inlet is excited with a harmonic pressure oscillation with an amplitude of 1.0 Pa, and the frequency resolution in the simulations is 20 Hz. The lossless Helmholtz wave equation has been solved for the numerical estimation (Jena et al, 2019), and the sound TL is estimated by TL ¼ 10 log 10 ðP in =P out Þ, where P in and P out are the sound power at inlet and outlet of the duct, respectively. The upstream and downstream segments of the duct contain an air medium of length l 4 ¼ 100 mm.…”

Section: Simulations and Discussionmentioning

confidence: 99%

“…The TL in the duct can be estimated analytically using the transfer matrix method (Munjal, 2014;Jena et al, 2019), and the transfer matrix of a block of air in a uniform duct without any scatters or porous materials can be expressed by…”

Section: Methods and Designmentioning

confidence: 99%

Sound transmission loss of porous materials in ducts with embedded periodic scatterers

Jena

Qiu

2020

The Journal of the Acoustical Society of America

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Porous materials that are commonly used for sound absorption have poor sound insulation capability. In this paper, rigid scatterers are installed periodically inside porous materials to improve their transmission loss (TL) with the Bragg diffraction. The Delany-Bazley impedance model is used to model the porous material and the transfer matrix method is adopted to calculate the TL of the mixed structure in a duct. Simulation results with a different number of scatterers and porous materials with different airflow resistivity show that the TL of porous materials can be increased significantly with periodically arranged scatterers. The decoupled analysis reveals that the TL of the mixed structure is larger than the sum of the TL of individual components in most frequency bands, except that around the first Bragg resonance frequency.

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Demonstration of effective acoustic properties of different configurations of Helmholtz resonators

Cited by 44 publications

References 26 publications

Design and Fabrication of Negative-Refractive-Index Metamaterial Unit Cells for Near-Megahertz Enhanced Acoustic Transmission in Biomedical Ultrasound Applications

Design and Fabrication of Negative-Refractive-Index Metamaterial Unit Cells for Near-Megahertz Enhanced Acoustic Transmission in Biomedical Ultrasound Applications

Resonansi Helmholtz: Pegas dalam Botol

Sound transmission loss of porous materials in ducts with embedded periodic scatterers

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