Velocity measurements in the oscillatory boundary layer produced by acoustic waves

Simultaneous amplitude and phase velocity measurements in the oscillatory viscous boundary layer (OVBL) produced by acoustic waves are reported. The structure of the OVBL of acoustic standing waves in air with frequencies of 35, 46, and 130 Hz is determined using hot-wire anemometry. The experimental results in amplitude are close to theoretical results of linear theories; small differences are pointed out. The phase results are in good agreement for 130 Hz, the agreement decreases for 35 and 46 Hz. A discussion on the possible causes of these discrepancies is made. Received: 25 May 2001/Accepted: 31 July 2001