Reproduction of acoustic evanescent waves using wave field synthesis by controlling phase differences between monopole secondary sources

Abstract

This paper is about the reproduction of acoustic evanescent waves using the linear distribution of discrete monopole secondary sources. The driving function for the actuation of a secondary source is derived using the theory of wave field synthesis. The analysis of the synthesized wave field is done for different source excitation frequencies. A new method of creating more precise evanescent waves based on the phase difference between the sources is also presented. The simulation result shows that the driving function obtained using the WFS method results in the correct synthesis of evanescent wave below aliasing frequency. Above the aliasing frequency, when the consecutive secondary sources are in antiphase, it will produce evanescent waves. Otherwise, propagating plane waves get produced. Different errors in the reproduced wave field which comes due to the use of discrete and fixed array length are also investigated, and some solutions to mitigate those errors are presented.