Flow measurements in a bass recorder using particle image velocimetry

The timbre of wind instruments is determined by the generation of standing waves inside the instrument. These can be studied by analyzing the acoustic pressure and flow oscillations of the air column. Particle Image Velocimetry (PIV) is a powerful tool capable of non-intrusively measuring air flow inside a tube. However, only a few studies have considered the application of time-resolved PIV to measure air flow inside a wind instrument. In this study, flow is measured inside a custom-made transparent recorder tube under natural playing conditions, during steady state. By collecting detailed flow measurements, this work aims to investigate the complex interactions between the air flow and the tone hole geometry of the instrument. The tone hole geometry is varied in diameter, height, and shape during the experiments. These findings have potential implications for wind instrument makers and could lead to a deeper understanding of sound production and articulation mechanisms in wind instruments. The study presents observations and discusses the broader relevance of PIV in wind instrument acoustics research.