SIDLAB: New 1D sound propagation simulation software for complex duct networks

Abstract

Low frequency sound generation and propagation in duct and pipe systems is important in many applications. The examples range from ventilation systems to IC-engine exhaust and inlet systems. Plane wave two-port theory can be used to describe the sound transmission along the system. Based on a long experience of different applications, a new user-friendly software (SIDLAB) has been developed to meet today's engineering needs. The new software is MATLAB based and allows access to the source code. This gives the user a flexibility to do other calculations than those already defined and further post-process the data. SIDLAB includes typical two-port elements for many applications but also unique elements, e.g., for modelling devices for exhaust gas cleaning. It is also unique that the two-port elements are allowed to be active, i.e., contain sources. There is no limitation to the number of elements and they can be connected together in any arbitrary scheme. By introducing one-port elements, the network can handle several inlets and outlets. SIDLAB can simulate passive results, such as transmission loss and transfer matrices between arbitrary nodes (points) in the network. It can also simulate active results, such as pressure and sound power at each node in the network. In this paper an overview of the new software is presented together with an example of the analysis of a complex muffler.