Sound Source Identification in a Rectangular Duct Based on the Equivalent Source Method

Identification of sources in a duct is an important experimental method to study the generation and propagation mechanism of sources in a duct. However, the previous identification methods in the duct mainly focus on the sources in a circular duct. In practical engineering, the sources in a rectangular duct are also more common, such as the aircraft model in a closed tunnel and the propeller model in a water channel. Therefore, it has essential engineering value to establish an identification method in a rectangular duct. In this paper, according to the principle of sound radiation of sources in an infinite rectangular duct, a sound source identification method based on the equivalent source method is developed. By establishing the transfer matrix between the sound pressure of each measuring point and the equivalent source strength, the equivalent source strength can be solved based on the measured pressures. Then, the solved equivalent source strength can be used to identify sound sources and predict sound fields. The simulation results show that the proposed method locates the sources and predicts the pressure at any position in the rectangular duct accurately. The results from a preliminary experiment also demonstrate that the proposed method can realize the source localization and sound field prediction.