Reconstruction of Acoustic Velocity Field Excited by Complex Tones by Means of Particle Image Velocimetry

The paper addresses a problem of the measurement and reconstruction of an acoustic velocity field using the particle image velocimetry technique (PIV). Nowadays this technique has become more and more popular non-invasive method of the sound field investigation. Using a so called phase-locked PIV there is possible to visualize sound fields excited by pure tones. In the paper some introductory results of numerical experiments are shown, which address the visualization of sound field excited by more complex signals -the sum of several sinusoids with different amplitude sets and frequency spacing. The experiments show, that the visualization of such field is a not straightforward task but it seems to be possible to achieve competent results. The main problem, which should be overcome is the correction of systematic error introduced by PIV system due to non-zero time interval between acquisition of two adjacent images of the field under investigation seeded by probe particles. Without the correction the reconstructed field is distorted due to different amplitude and phase shifts of its spectral components. Some notes on the correction method has been presented in that paper.