Acoustic-Structure Interaction in an Adaptive Helmholtz Resonator by Compliance and Constraint

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Shichao Cui ◽  
Ryan L. Harne
Keyword(s):  
Flexible Structures ◽  
Helmholtz Resonator ◽  
Acoustic Resonator ◽  
Acoustic Energy ◽  
Coupled Resonators ◽  
Acoustic Structure ◽  
Structure Interaction ◽  
Helmholtz Resonators ◽  
Rigid Walls ◽  
Flexible Member

Abstract The acoustic energy attenuation capabilities of traditional Helmholtz resonators are enhanced by various methods, including by coupled resonators, absorbing materials, or replacement of rigid walls with flexible structures. Drawing from these concepts to envision a new platform of adaptive Helmholtz resonator, this research studies an adaptive acoustic resonator with an internal compliant structural member. The interaction between the structure and acoustic domain is controlled by compression constraint. By applying uniaxial compression to the resonator, the flexible member may be buckled, which drastically tailors the acoustic-structure interaction mechanisms in the overall system. A phenomenological analytical model is formulated and experimentally validated to scrutinize these characteristics. It is found that the compression constraint may enhance damping capabilities of the resonator by adapting the acoustic-structure interaction between the resonator and the enclosure. The area ratio of the flexible member to the resonator opening and the ratio of the fundamental natural frequency of the flexible member to that of the enclosure are discovered to have a significant influence on the system behavior. These results reveal new avenues for acoustic resonator concepts exploiting compliant internal structures to tailor acoustic energy attenuation properties.

Energy Extraction-Based Robust Linear Quadratic Gaussian Control of Acoustic-Structure Interaction in Three-Dimensional Enclosure

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
F. Liu ◽  
B. Fang ◽  
A. G. Kelkar
Keyword(s):  
Three Dimensional ◽  
Boundary Surface ◽  
Acoustic Energy ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Acoustic Structure ◽  
Structure Interaction ◽  
Weighting Matrix ◽  
Simulation And Experiment ◽  
Identification Techniques

This paper presents an linear quadratic Gaussian (LQG)-based robust control strategy for active noise reduction in a 3D enclosure wherein acoustic-structure interaction dynamics is present. The acoustic disturbance is created by the piezo-actuated vibrating boundary surface of the enclosure. The control signal is generated by the speaker which is noncollocated with the sensing microphone mounted inside the enclosure. The dynamic model of the system is obtained using frequency-domain system identification techniques. The state weighting matrix in the LQG cost function is determined analytically in the closed-form which allows the control designer to directly penalize the total acoustic energy of the system. The robustness of the controller is also ensured to guarantee the closed-loop stability against the unmodeled dynamics and parametric uncertainties. Simulation and experiment results are given which demonstrate the effectiveness of the proposed control methodology.

Modelling of Circumferential Modal Coupling Due to Helmholtz Resonators

2003 ◽  
Author(s):  
Simon R. Stow ◽  
Ann P. Dowling
Keyword(s):  
Acoustic Waves ◽  
Gas Turbines ◽  
Helmholtz Resonator ◽  
Operating Conditions ◽  
Acoustic Energy ◽  
Radial Dependence ◽  
Helmholtz Resonators ◽  
Annular Duct ◽  
Linear Waves ◽  
Modal Coupling

Lean premixed prevaporised (LPP) combustion can reduce NOx emissions from gas turbines, but often leads to combustion instability. Acoustic waves produce fluctuations in heat release, for instance by perturbing the fuel-air ratio or flame shape. These heat fluctuations will in turn generate more acoustic waves and in some situations self-sustained oscillations can result. A linear model for thermoacoustic oscillations in LPP combustors is described. A thin annular geometry is assumed and so circumferential modes are included but radial dependence is ignored. The formulation is in terms of a network of modules such as straight ducts and area changes. At certain operating conditions, the flow is predicted to be unstable, with linear waves growing in amplitude. Helmholtz resonators can be used to absorb acoustic energy and, when carefully designed and installed at appropriate locations, can stabilise the flow. Helmholtz resonators are included in the model. Connecting a Helmholtz resonator to an annular duct destroys the axisymmetry of the geometry. This results in coupling of the circumferential modes which must be calculated. The model is used to investigate the best arrangement of resonators around the circumference of an annular duct to achieve maximum damping of a circumferential oscillation.

Analysis of Acoustic-Structure Interaction Using a High-Order Doubly Asymptotic Approximation

2016 ◽  
Vol 24 (01) ◽  
pp. 1550021 ◽  
Author(s):  
Heekyu Woo ◽  
Young S. Shin
Keyword(s):  
Order Approximation ◽  
Stable Model ◽  
Approximation Model ◽  
Third Order ◽  
Acoustic Structure ◽  
Structure Interaction ◽  
Proposed Model ◽  
The Stability ◽  
Third Order Approximation ◽  
Interaction Problem

In this paper, a new third-order approximation model for an acoustic-structure interaction problem is introduced. The new approximation model is designed to be an accurate and a stable model for predicting the response of a submerged structure. The proposed model is obtained by combining two lower order approximation models instead of using an operator matching method. The stability of this model is checked by a modal analysis. Finally, the approximation model is coupled to the spherical shell structure, and its performance is checked by a shock analysis.

scholarly journals Experimental Study of Advanced Helmholtz Resonator Liners with Increased Acoustic Performance by Utilising Material Damping Effects

2018 ◽  
Vol 8 (10) ◽  
pp. 1923
Author(s):  
Martin Dannemann ◽  
Michael Kucher ◽  
Eckart Kunze ◽  
Niels Modler ◽  
Karsten Knobloch ◽  
...  
Keyword(s):  
Polymer Films ◽  
Helmholtz Resonator ◽  
Broadband Noise ◽  
Acoustic Energy ◽  
Acoustic Damping ◽  
Acoustic Performance ◽  
Acoustic Liners ◽  
Flexible Polymer ◽  
Noise Absorption ◽  
Aero Engines

In aero engines, noise absorption is realised by acoustic liners, e.g., Helmholtz resonator (HR) liners, which often absorb sound only in a narrow frequency range. Due to developments of new engine generations, an improvement of overall acoustic damping performance and in particular more broadband noise absorption is required. In this paper, a new approach to increase the bandwidth of noise absorption for HR liners is presented. By replacing rigid cell walls in the liner’s honeycomb core structure by flexible polymer films, additional acoustic energy is dissipated. A manufacturing technology for square honeycomb cores with partially flexible walls is described. Samples with different flexible wall materials were fabricated and tested. The acoustic measurements show more broadband sound absorption compared to a reference liner with rigid walls due to acoustic-structural interaction. Manufacturing-related parameters are found to have a strong influence on the resulting vibration behaviour of the polymer films, and therefore on the acoustic performance. For future use, detailed investigations to ensure the liner segments compliance with technical, environmental, and life-cycle requirements are needed. However, the results of this study show the potential of this novel liner concept for noise reduction in future aero-engines.

scholarly journals The effect of type of sound damper material in the Helmholtz resonator to the output power spectrum of acoustic energy Harvester

2019 ◽  
Vol 3 (2) ◽  
pp. 50
Author(s):  
Hedwigis Harindra ◽  
Agung Bambang Setio Utomo ◽  
Ikhsan Setiawan
Keyword(s):  
Energy Harvesting ◽  
Power Spectrum ◽  
Electric Power ◽  
Energy Harvester ◽  
Helmholtz Resonator ◽  
Acoustic Energy ◽  
Acoustic Energy Harvesting ◽  
Wasted Energy ◽  
Second Peak ◽  
Output Electric Power

<span>Acoustic energy harvesting is one o</span><span lang="EN-US">f</span><span> many ways to harness </span><span lang="EN-US">acoustic </span><span>noises as wasted energy into use</span><span lang="EN-US">f</span><span>ul </span><span lang="EN-US">electical </span><span>energy using an acoustic </span><span>energy harvester. </span><span>Acoustic </span><span>energy harvester t</span><span lang="EN-US">h</span><span>at tested by Dimastya (2018) </span><span lang="EN-US">which is consisted of loudspeake</span><span>r </span><span lang="EN-US">and Helmholtz resonator, </span><span>produced two-peak spectrum. It is </span><span lang="EN-US">suspected</span><span> that the </span><span lang="EN-US">f</span><span>irst peak </span><span lang="EN-US">is due t</span><span>o </span><span lang="EN-US">Helmholtz</span><span> resonator resonance and the second peak </span><span lang="EN-US">comes</span><span lang="EN-US">from the resonance of the conversion </span><span>loudspeaker. </span><span lang="EN-US">This research is to experimentally confirm the guess of the origin of the first peak. The experiments are performed by adding silencer materials on the resonator inner wall which are expected to be able to reduce the height of first peak and to know </span><span>how </span><span lang="EN-US">they</span><span> a</span><span lang="EN-US">ff</span><span>ect t</span><span>he output electric power spectrum o</span><span lang="EN-US">f</span><span> t</span><span>he acoustic energy harvester. </span><span lang="EN-US">Three different silencer materials are used, those are</span><span> glasswool, acoustic </span><span lang="EN-US">f</span><span>oam, and styro</span><span lang="EN-US">f</span><span>oam</span><span lang="EN-US">,</span><span> with</span><span lang="EN-US"> the same thickness of</span><span> 12 cm. </span><span lang="EN-US">The r</span><span>esult</span><span lang="EN-US">s</span><span> show that glasswool absorb</span><span lang="EN-US">s</span><span> sound more e</span><span lang="EN-US">ff</span><span>ectively than acostic </span><span lang="EN-US">f</span><span>oam and styro</span><span lang="EN-US">f</span><span>oam. The use o</span><span lang="EN-US">f</span><span> glasswool, acoustic </span><span lang="EN-US">f</span><span>oam, and styro</span><span lang="EN-US">f</span><span>oam with 12 cm thickness lowered the </span><span lang="EN-US">f</span><span>irst peak </span><span lang="EN-US">by</span><span> 90% (</span><span lang="EN-US">f</span><span>rom 39 mW to 0,5 mW), 82% (</span><span lang="EN-US">f</span><span>rom 39 mW to 0,7 mW), and 82% (</span><span lang="EN-US">f</span><span>rom 39 mW to 0,7 mW), respectively. </span><span lang="EN-US">Based on these results, it is concluded that the guess of the origin of the first peak is confirmed.</span>

A panel acoustic energy harvester based on the integration of acoustic metasurface and Helmholtz resonator

2021 ◽  
Vol 119 (25) ◽  
pp. 253903
Author(s):  
Xiaobin Cui ◽  
Jinjie Shi ◽  
Xiaozhou Liu ◽  
Yun Lai
Keyword(s):  
Energy Harvester ◽  
Helmholtz Resonator ◽  
Acoustic Energy

Numerical study for increasement of low frequency sound insulation of double-panel structure using sonic crystals with distributed Helmholtz resonators

2019 ◽  
Vol 33 (14) ◽  
pp. 1950138
Author(s):  
Myong-Jin Kim
Keyword(s):  
Free Space ◽  
Transmission Loss ◽  
Numerical Study ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Sound Insulation ◽  
The Finite Element Method ◽  
Helmholtz Resonators ◽  
Sonic Crystal ◽  
Sonic Crystals

Numerical simulations of the sound transmission loss (STL) of a double-panel structure (DPS) with sonic crystal (SC) comprised of distributed local resonators are presented. The Local Resonant Sonic Crystal (LRSC) consists of “C”-shaped Helmholtz resonator columns with different resonant frequencies. The finite element method is used to calculate the STL of such a DPS. First, the STLs of LRSC in free space and the DPS with LRSC are calculated and compared. It is shown that the sound insulations of the local resonators inserted in the double panel are higher than that in free space for the same size of the SCs and the same number of columns. Next, STL of the DPS in which the SC composed of three columns of local resonators having the same outer and inner diameters but different slot widths are calculated, and a reasonable arrangement order is determined. Finally, the soundproofing performances of DPS with distributed LRSC are compared with the case of insertion of general cylindrical SC for SC embedded in glass wool and not. The results show that the sound insulation of the DPS can be significantly improved in the low frequency range while reducing the total mass without increasing the thickness.

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