Analysis of discontinuities in rectangular ducts and higher order mode excitations using TLM and FEM methods

✍ Scribed by Samir El-Masri

• Book ID: 102907548
• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 611 KB
• Volume: 17
• Category: Article
• ISSN: 0894-3370
• DOI: 10.1002/jnm.532

✦ Synopsis

Abstract

In acoustic waveguide, it is believed that higher order modes have a dramatic effect on the behaviour of the global acoustic waves when the frequency of the source is above the cut‐off frequency of the duct. In this paper, we are going to study the influence of the discontinuities on the excitation and the propagation of higher order modes in symmetrical and non‐symmetrical ducts using theoretical analysis and numerical simulations. As for numerical simulations, transmission line matrix (TLM) method and finite element method (FEM) will be used. Moreover, we will try here to compare the two numerical methods, showing their advantages and disadvantages. The transfer functions of symmetrical and non‐symmetrical ducts will also be shown and discussed as well as numerical simulations of the acoustic pressure into the duct in three‐dimensional (3‐D) system. Copyright © 2004 John Wiley & Sons, Ltd.