Boundary Element Method for Intensity Potential Approach: Predicting the Radiated Sound Power from Partially Enclosed Noise Sources

2012 ◽  
Vol 98 (4) ◽  
pp. 588-599 ◽  
Author(s):  
Patrik B. U. Andersson ◽  
Eskil Lindberg
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Sound Power ◽  
Noise Sources ◽  
Potential Approach ◽  
Radiated Sound ◽  
Radiated Sound Power ◽  
Element Method

ENFORCING RECIPROCITY IN NUMERICAL ANALYSIS OF ACOUSTIC RADIATION MODES AND SOUND POWER EVALUATION

2012 ◽  
Vol 20 (03) ◽  
pp. 1250005 ◽  
Author(s):  
HERWIG PETERS ◽  
NICOLE KESSISSOGLOU ◽  
STEFFEN MARBURG
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Radiation ◽  
Sound Power ◽  
Impedance Matrix ◽  
Radiated Sound ◽  
The Asymmetry ◽  
Power Evaluation ◽  
Radiated Sound Power ◽  
Element Method

By identifying the efficiently radiating acoustic radiation modes of a fluid loaded vibrating structure, the storage requirements of the acoustic impedance matrix for calculation of the sound power using the boundary element method can be greatly reduced. In order to compute the acoustic radiation modes, the impedance matrix needs to be symmetric. However, when using the boundary element method, it is often found that the impedance matrix is not symmetric. This paper describes the origin of the asymmetry of the impedance matrix and presents a simple way to generate symmetry. The introduction of additional errors when symmetrizing the impedance matrix must be avoided. An example is used to demonstrate the behavior of the asymmetry and the effect of symmetrization of the impedance matrix on the sound power. The application of the technique presented in this work to compute the radiated sound power of a submerged marine vessel is discussed.

Acoustic Radiation Simulation of Marine Sliding-Thrust Bearing Shell Based on SYSNOISE

2011 ◽  
Vol 291-294 ◽  
pp. 1961-1964
Author(s):  
Guang Liang Zhao
Keyword(s):  
Dynamic Analysis ◽  
Boundary Element ◽  
Thrust Bearing ◽  
Acoustic Radiation ◽  
Element Model ◽  
Sound Power ◽  
Supporting Structure ◽  
Radiated Sound ◽  
The Impact ◽  
Radiated Sound Power

This paper takes marine Kingsbury sliding thrust bearing as the research object and conducts the finite element dynamic analysis with the aid of ANSYS software. On this basis, the acoustic boundary element model of a sliding thrust bearing shell is established with the ANSYS dynamic analysis results as the boundary excitation conditions. Besides, the radiated sound power of the shell is calculated by indirect boundary element method in SYNOSISE software. The influence of different condition parameters on the radiated sound power of the shell is perceived through the analysis of several rotation-thrust conditions. As for the special structure of this kind of sliding-thrust bearing, this paper states the impact of the supporting structure performance parameters, the pad number and damp of shell on the shell radiated sound power. The optimized measure for the supporting structure and the plan concerning the pad number’s selection lays the theoretical basis for damping and noise-reducing research on marine sliding-thrust bearing and its rotor system.

COMBINATION OF FUZZY ARITHMETIC AND A FAST BOUNDARY ELEMENT METHOD FOR ACOUSTIC SIMULATION WITH UNCERTAINTIES

2009 ◽  
Vol 17 (01) ◽  
pp. 45-69 ◽  
Author(s):  
M. JUNGE ◽  
D. BRUNNER ◽  
J. BECKER ◽  
M. MAESS ◽  
J. ROSEIRA ◽  
...  
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Sound Velocity ◽  
Fuzzy Numbers ◽  
Structural Parameters ◽  
Acoustic Properties ◽  
Fuzzy Arithmetic ◽  
Driving Frequency ◽  
Radiated Sound ◽  
Element Method

A so-called FuzzBEM methodology for analyzing the influence of uncertain acoustic and structural parameters on the radiated sound field of vibrating structures combining fuzzy arithmetic and fast multipole boundary element method is introduced. Uncertainties in acoustic properties may result from uncertain parameters of the vibrating mechanical structures, e.g. material density or geometry, as well as from uncertainties in the acoustic domain, e.g. sound velocity. The use of the transformation method in the proposed approach allows to employ simulation tools based on the crisp number arithmetic by appropriate preprocessing of the fuzzy numbers modeling the uncertain input parameters and postprocessing of the simulation results to determine the fuzzy numbers for the considered output quantities. In this contribution, the proposed FuzzBEM procedure is applied to a sound radiating, vibrating stiffened cylindrical shell where the investigated uncertainties include the shell wall thickness and the driving frequency of a monofrequency point load and the air density and sound velocity. As exemplary output quantities of acoustic performance, the acoustic pressure at multiple field points and the radiated sound power are evaluated. The proposed coupling of fuzzy arithmetic and acoustic boundary elements yields run times two orders of magnitudes or more longer than a single BEM calculation. Nevertheless, the systematic parameterization obtained by the proposed fuzzy analysis has the potential to reveal input–output relationships difficult to identify with individual conventional BEM simulation runs.

Study on the Simulation Method of Compressor Aerodynamic Noise Based on CFD and IBEM

2016 ◽  
Author(s):  
Liu Chen ◽  
Cao Yipeng ◽  
Sun Wenjian ◽  
Zhang Wenping ◽  
Ming Pingjian ◽  
...  
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Fluid Dynamic ◽  
Simulation Method ◽  
Aerodynamic Noise ◽  
Noise Sources ◽  
Indirect Boundary Element Method ◽  
Unsteady Viscous Flow ◽  
Radiation Noise ◽  
Element Method

Turbocharger compressor aerodynamic noise has been one of the major noise sources of diesel engine. It is necessary to study the characteristics of turbocharger fluid flow and radiation noise for its effective noise control. In this paper, a new for predicting compressor aerodynamic noise is presented, which combined the computational fluid dynamic (CFD) and indirect boundary element method (IBEM). The unsteady viscous flow in compressor was simulated based on the finite volume method. In addition, the periodic pressure fluctuation of the rotor inlet and blades were used to compressor radiation noise field simulation by indirect boundary element method. In order to prove the feasibility of numerical simulation, the acoustics experimental device for compressor aerodynamic noise experiment was built and the sound pressure of turbocharger were tested. The trend of simulation results and amplitude level in blade passing frequency (BPF) coincide with the experiment results. It indicates that the coupling method is more effective and accurate in turbocharger noise prediction.

Sound Radiation Response of a Rectangular Plate Having a Side Crack of Arbitrary Length, Orientation, and Position

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Tanmoy Bose ◽  
Amiya R. Mohanty
Keyword(s):  
Rectangular Plate ◽  
Ritz Method ◽  
Sound Radiation ◽  
Radiation Efficiency ◽  
Sound Power ◽  
Cracked Plate ◽  
Side Crack ◽  
Radiated Sound ◽  
Radiated Sound Power ◽  
Element Method

Here, sound radiation characteristics of a rectangular plate having a side crack of different crack lengths, orientations, and positions are studied considering clamped boundary conditions. First, a free and forced vibration response analysis of a cracked plate is done using the Ritz method. Orthogonal polynomials are used for faster convergence and some corner functions are used to generate the effect of a crack. Radiated sound power and radiation efficiency of the cracked plate are computed by the quadruple integration. A convergence test of radiation efficiency is carried out to fix the number of polynomials and corner functions in the analysis. It is found that the radiation efficiency and radiated sound power computed by the Ritz method are close to the same obtained from the boundary element method (BEM). The natural frequencies computed using the Ritz method are also found to be close to that obtained from the finite element method (FEM). The radiation efficiency curves of different modes are shown for a change in crack length, orientation and position. Finally, the variations of normalized sound power are shown to be due to a change in the crack parameters.

scholarly journals An Adjoint Operator Approach for Sensitivity Analysis of Radiated Sound Power in Fully Coupled Structural-Acoustic Systems

2017 ◽  
Vol 25 (01) ◽  
pp. 1750003 ◽  
Author(s):  
Leilei Chen ◽  
Steffen Marburg ◽  
Haibo Chen ◽  
Hao Zhang ◽  
Hongbo Gao
Keyword(s):  
Sensitivity Analysis ◽  
Adjoint Operator ◽  
Design Sensitivity ◽  
Sound Power ◽  
Operator Approach ◽  
Design Variables ◽  
Structural Density ◽  
Radiated Sound ◽  
Radiated Sound Power ◽  
Element Method

Full interaction between structural and fluid domains must be considered for light structures immersed in heavy fluid (e.g. thin steel shells in water). The structural-acoustic design sensitivity analysis provides information on the effect of the design variable on acoustic performance, which makes it a key step for noise control and structural-acoustic optimization. This study uses the finite element method (FEM) to model the structure domain, while the fast multipole boundary element method (BEM) is applied to the exterior acoustic domain. An adjoint operator approach is developed to calculate the sensitivity of the radiated sound power with respect to the design variables, which can be any structural or fluid parameter (e.g. fluid or structural density, Poisson’s ratio, Young’s modulus, and geometric measures). Numerical examples are presented to demonstrate the validity and efficiency of the proposed algorithm.

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