Reconstructing the Directivity Pattern of a Sound Source in Free Space by Measuring its Field in a Tank

Abstract

The paper discusses reconstruction of the directivity pattern of a sound source in free space from measurements of the field excited by this source in a tank. The reconstruction procedure uses a reference acoustic monopole. The field of the calibrated source is compared with the fields emitted by the monopole from several specially selected points of the tank. The signals of the source and reference monopole are recorded by the same receivers. From these measurements, the field of the source in the tank is approximated by superposing the fields of the acoustic monopoles. Conditions are formulated under which the field of the source in free space can be represented as the superposed fields of the same monopoles. This makes it possible to calculate the directivity pattern of the calibrated source in free space. The efficiency of the method is confirmed by numerical simulation results.