TLM Modelling Of Acoustic Devices

Abstract

The Transmission Line Matrix (TLM) method can be used to solve the wave equation numerically. It has been applied very widely in electromagnetics, less in acoustics. Propagation is modelled by pulses travelling through a grid or "matrix" of ideal transmission lines, thereby discretising the space of interest. During each time increment the pulses are assumed to travel from node to node in the grid, where they scatter according to a simple pattern. If the mesh is fine enough, the process models the wave equation. The focus of this paper is on the TLM modelling of acoustic devices such as microphones, in which mechanical-acoustic interaction plays a central role. A computer model of the device is easily built up by combining rectangular TLM "building blocks" or arrays