Three-dimensional/one-dimensional numerical correlation study of a three-pass perforated tube

The Prediction of the Performance and Gasdynamic Noise Emitted by a Medium-Size Spark-Ignition Engine by Means of 1D and 3D Analyses

https://www.matelys.com/publications/CP11.pdf

Coupling transfer matrix method to finite element method for analyzing the acoustics of complex hollow body networks

Transfer matrix methods for sound attenuation in resonators with perforated intruding inlets

This paper considers the combined use of a hybrid numerical method for the modeling of acoustic mufflers and a genetic algorithm for multiobjective optimization. The hybrid numerical method provides accurate modeling of sound propagation in uniform waveguides with non-uniform obstructions. It is based on coupling a wave based modal solution in the uniform sections of the waveguide to a finite element solution in the non-uniform component. Finite element method provides flexible modeling of complicated geometries, varying material parameters, and boundary conditions, while the wave based solution leads to accurate treatment of non-reflecting boundaries and straightforward computation of the transmission loss (TL) of the muffler. The goal of optimization is to maximize TL at multiple frequency ranges simultaneously by adjusting chosen shape parameters of the muffler. This task is formulated as a multiobjective optimization problem with the objectives depending on the solution of the simulation model. NSGA-II genetic algorithm is used for solving the multiobjective optimization problem. Genetic algorithms can be easily combined with different simulation methods, and they are not sensitive to the smoothness properties of the objective functions. Numerical experiments demonstrate the accuracy and feasibility of the model-based optimization method in muffler design.

/pdf/multiobjective-muffler-shape-optimization-with-hybrid-1qz8vfpp8g.pdf

Multiobjective muffler shape optimization with hybrid acoustics modeling

Mufflers are widely used for exhaust noise attenuation in vehicles and machinery. Recent advances in modeling procedures for accurate performance prediction have led to the development of modeling methods for practical muffler components in commercial design. Muffler designers need simple and fast modeling tools, especially in the preliminary design evaluation stages. Finite Element and Boundary Element methods are often used to provide valid results in a wide range of frequencies. However, these methods are time-consuming, its use needs highly trained personnel and the commercial software is usually quite expensive. Therefore, plane wave based models such as the transfer matrix method (TMM) can offer fast initial prototype solutions for muffler designers. In this paper, the principles of TMM for predicting the transmission loss (TL) of a muffler are summarized. The method is applied to different muffler configurations and the numerical predictions are compared with the results obtained by means of an experimental set up. Only stationary, non-dissipative mufflers are considered. The limitation of both the experimental method and the plane wave approach are discussed. The predicted results agreed reasonably well with the measured results in the low frequency range where the firing engine frequency and its first few harmonics are the main sources of noise.

/pdf/muffler-modeling-by-transfer-matrix-method-and-experimental-aikthrc4qt.pdf

J. L. Bento Coelho

Papers

Muffler modeling by transfer matrix method and experimental verification