Linear Acoustic Holography Method for High-speed Train Sound Field Reconstruction

摘要

The far-field acoustic holography (FAH) method has been widely used for high-speed train sound field reconstruction. However, the angle resolution for FAH gets worse when the sound source is farther away from the orthographic projection of the microphone array center. In other words, the edge distortion effect gets more serious when the target sound sources distribute in a larger space. Normally, the high-speed trains in China contains 8 or 16 carriages, which corresponds to 202 m or 404 m long, and 6 m high, leading to significant edge distortion effect. To solve the sound field reconstruction problem for high-speed sound sources in large space, this paper develops a linear acoustic holography method. Firstly, the Doppler effect of high-speed sound sources is eliminated based on derivations from three-dimensional inhomogeneous wave equation. Secondly, the linear sound field orthogonal projected to microphone array center is reconstructed using far-field Kirchhoff diffraction integration acoustic holography method. Thirdly, the planar sound field is reproduced taking advantages of vehicle's movement. This method has been validated by 280 km/h high-speed train experiments. The results show that this method can solve the edge distortion problem and obtain accurate sound field reconstructions and precise sound source localizations.