Finite element analysis for acoustic characteristics of combustion stabilization devices

Kim, Seong-Ku; Choi, Hwan Seok; Kim, Hong-jip; Young-Sung, Ko; Sohn, Chae Hoon

doi:10.1016/j.ast.2015.01.024

Cited by 21 publications

(8 citation statements)

References 16 publications

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“…in which β is the media acoustic admittance [33]. For algorithm research, β is set to be 0 for rigid-backing, and is set to 1 for a full sound-absorbing effect which could be regarded as nonreflecting boundary conditions [34].…”

Section: Boundary Element Formulation For Sound Radiationmentioning

confidence: 99%

Sensitivity Analysis for Coupled Structural-Acoustic System with Absorbing Material Using FEM/BEM

2021

IJEM

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Since the acoustic impedance in water cannot be neglected with respect to the mechanical impedance, the acoustic radiation caused by the vibration of structures in the compressible fluid would react to the structure. Therefore, the fluid-structure interaction needs to be considered. The finite element method is used for structure vibration analysis and the boundary element method for acoustic analysis. Sound absorption materials are used to reduce the scattering sound field in the reference region. The sensitivity analysis of a fully coupled structural-acoustic system is proposed. Numerical tests verify the correctness of the proposed algorithm.

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Section: Boundary Element Formulation For Sound Radiationmentioning

confidence: 99%

Sensitivity Analysis for Coupled Structural-Acoustic System with Absorbing Material Using FEM/BEM

2021

IJEM

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“…Instead of solving the non-symmetric linear equations by using an iterative solver, we propose the next approach. By substituting equation 4into equation 13, we can obtain the coupled boundary element equation, as follows: (15) in which…”

Section: Fem/bem Coupling Formulationsmentioning

confidence: 99%

“…Directly solving the term A -1 C sf p in equation (15) could consume considerable time. In this paper, we use the fast multipole method and the iterative solver generalized minimal residual method (GMRES) to accelerate the calculation of the solution to the coupled boundary element system equation.…”

Section: Fem/bem Coupling Formulationsmentioning

confidence: 99%

“…Special effort is devoted to numerically obtain the absorption coefficient and acoustic conductance. For the generalization of the boundary conditions [14], the acoustic admittance  could be introduced, which tends to be zero at perfectly reflecting boundaries like a rigid wall [15]. On the other hand, for non-reflecting boundary conditions, =1.…”

Section: Introductionmentioning

confidence: 99%

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FEM/FMBEM coupling for acoustic structure interaction and acoustic design sensitivity analysis with sound-absorbing materials

Yang

Chen

2015

WIT Transactions on Modelling and Simulation

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For thin structures immersed in water, a full interaction between the structural domain and the fluid domain needs to be taken into account. In this work, the finite element method (FEM) is used to model the structure parts, while the boundary element method (BEM) is applied to the exterior acoustic domain. A coupling algorithm based on FEM and the wideband fast multipole BEM (FEM/Wideband FMBEM) is used for the simulation of acoustic-structure interaction. The Burton-Miller formulation is used to overcome the fictitious frequency problem when using a single Helmholtz boundary integral equation for exterior boundary-value problems. Structural-acoustic design sensitivity analysis is performed based on the coupling formulation. The design variable can be chosen as the material parameters, structure and fluid parameters, such as the fluid density, structural density, Poisson's ratio, Young's modulus, structural shape size and so on. Furthermore, the impact of sound-absorbing material on the scattering problem for structures underwater is researched. The acoustic admittance of the soundabsorbing material has also been chosen as the design variable for the sensitivity analysis. Numerical example is presented to demonstrate the validity and efficiency of the proposed algorithm.

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“…Undesirable tonal or broadband acoustic noise is present in aero-engines or gas turbine engines. [1][2][3][4][5] To dissipate this noise, Helmholtz resonators are widely implemented in the engine systems. 6,7 In practical engines, a Helmholtz resonator may be attached to a combustor to dampen thermoacoustic instability, 8 as a grazing flow is present.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of transmission loss performances of asymmetric Helmholtz resonators in the presence of a grazing flow

Pan

Guan

2018

Journal of Low Frequency Noise, Vibration and Active Control

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As a typical noise-attenuating device, Helmholtz resonators are widely implemented in aero-engines and gas turbines to decrease the transmission of acoustic noise. However, an asymmetric Helmholtz resonator could be designed and implemented due to the limited space available in the engines. To examine and optimize the noise-attenuating performances of the asymmetric resonator, comparison studies are performed. For this, a two-dimensional frequency-domain model of a cylindrical duct with a grazing flow is developed. An asymmetric Helmholtz resonator is attached as a side branch. The model containing the linearized Navier-Stokes equations is validated first by comparing the predicted results with the experimental ones available in the literature. Further validation is conducted by comparing the results of an asymmetric resonator with the analytical ones available in the literature. The effects of (1) neck offset distance from the center of the resonator cavity denoted by e c =a s and (2) the grazing flow Mach number M u are evaluated. It is shown that as the grazing flow Mach number is increased, the resonant frequencies and the maximum transmission losses are dramatically varied for a given e c =a s. As e c =a s is increased from 0 to 0.5 and M u ! 0:1, the resonant frequencies and the maximum transmission losses are increased. However, when M u is lower than 0.07, i.e. M u 0:07, the transmission loss performances are almost unchanged with e c =a s increased. The optimum design of the asymmetric resonator is shown to give rise to the resonant frequency being shifted by 10% and 2-5 dB more transmission loss at higher Mach number. Finally, visualization of vortex shedding formed at the neck of the asymmetric resonator confirms that acoustical energy is transformed into kinetic energy and absorbed by the surrounding air. This study opens up a numerical design approach to optimize an asymmetric resonator.

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Finite element analysis for acoustic characteristics of combustion stabilization devices

Cited by 21 publications

References 16 publications

Sensitivity Analysis for Coupled Structural-Acoustic System with Absorbing Material Using FEM/BEM

Sensitivity Analysis for Coupled Structural-Acoustic System with Absorbing Material Using FEM/BEM

FEM/FMBEM coupling for acoustic structure interaction and acoustic design sensitivity analysis with sound-absorbing materials

Numerical studies of transmission loss performances of asymmetric Helmholtz resonators in the presence of a grazing flow

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