A Frequency Compensation Method to Smooth Frequency Fluctuation for Locating Moving Acoustic Sources

摘要

The current beamforming approach for locating moving acoustic sources could not correctly evaluate sources with time-dependent frequency fluctuation. The frequency fluctuation is usually caused by the non-constant relative speed between the solid object and the flow. The source frequency varies with time in a certain frequency range, so that the frequency-domain beamforming approach, which only focuses on a fixed narrow frequency band, cannot focus on the fluctuating frequencies. A frequency compensation method is proposed to smooth the frequency fluctuation. Fluctuating frequencies are squeezed into a narrow frequency band, so that a frequency fluctuating source can be treated as a conventional steady source. The method is then integrated into the frequency-domain beamforming approach for moving sources, and is able to identify moving sources with frequency fluctuation. The integrated method is verified by a simulation and an experiment performed on a rotating source.