Virtual Rotating Array for Near-Field Localization of Rotating Sound Sources

In this study, a more efficient time domain (TD) virtual rotating array (VRA) method is proposed that employs a zeroth-order interpolation scheme. The interpolation of sound fields in the receiver plane using only the nearest microphone at each time step improves the efficiency of the entire process. Additionally, the VRA method is demonstrated to function well with near-field acoustic holography for localizing rotating sound sources. The proposed methods are numerically and experimentally validated. The zeroth-order interpolation scheme is compared with linear, barycentric, and radial basis function schemes using either a circular array or an arbitrary array. The holographic reconstructions are compared for selected one-third octave band center frequencies. Compressive sensing-based holography is used for increasing the resolution of the numerical simulations at low frequencies. The source strength is calculated by integrating the holographic spectra in the source plane. A comparison of the predicted source strengths and locations suggests that the zeroth-order scheme yields a more accurate solution than higher-order schemes. The proposed zeroth-order scheme and the source reconstruction using VRA signals have the potential to visualize sound fields produced by compact rotating structures.