An investigation into time domain Doppler modelling using the TLM numerical method

The effects observed by a moving source and stationary receiver, or conversely stationary source and moving receiver are well known to physicists. The Doppler effect as it is commonly known is recognized as a perceived change in frequency of the incident signal upon the receiver, caused by the motion of either the source or receiver with respect to the stationary component, occurring in both electromagnetic (transverse) and acoustic (longitudinal) waves. This paper will primarily focus on the acoustic Doppler effect in the time domain, simulating a variety of scenarios using transmission line matrix (TLM) modelling in which the effect can be observed, proceeding to compare the accuracy of the various models generated. A new technique to allow arbitrary placement of boundaries of a TLM mesh will also be introduced and analysed allowing accurate placement of the moving walls within the simulation. Copyright © 2007 John Wiley & Sons, Ltd.