One dimensional, linear, plane-wave modelling of silencer systems in the frequency
domain provides an efficient means to analyse their acoustic performance. Software
packages are available to analyse silencers within these modelling parameters;
however, they are heavily restricted. The thesis develops an algorithm that increases
the computational efficiency of the silencer analysis.
The thesis concentrates on how data, within a software package, is stored, retrieved
and analysed. The computational efficiency is increased as a result of the predictable
patterns caused by the repetitive nature of exhaust system analysis. The work uses the
knowledge gained from the construction of two previous algorithms of similar
parameters; it isolates and maximises their advantages whilst minimising their
associated disadvantages. The new algorithm is dependent on identifying
consecutively sequenced exhaust components and sub-systems of such components
within the whole exhaust system.
The algorithm is further generalised to include multiple time-variant sources, multiple
radiation points and exhaust systems that have a balance pipe. Another feature of the
improved algorithm encompasses the option of modelling secondary noise sources
such as might arise from flow generated noise or be included for active noise
The validation of these algorithmic techniques is demonstrated by comparison of the
theoretical noise predictions with experimental or known results. These predictions are
achieved by writing computational code using object orientated programming
techniques in the language of c++ to implement the algorithms.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University