A technical note on modelling the effect of source motion on amplitude and Doppler shift using resampling

Rapport, 2023

Modelling of the sound field due to a simple monopole source moving at subsonic speed is investigated. It is shown that both the Doppler shift and the influence of the Doppler factor on the amplitude and the directivity can be modelled by a single resampling process demanding area conservation. This is the main novel contribution of the paper. Here, the Doppler factor is defined as $(1-u_r/c)^{-1}$, where $u_r$ is the component of the moving source velocity in the direction of the receiver and $c$ is the sound speed. The paper may contribute to an increased understanding of the reasons for the Doppler factor in relation to higher order convective factors.