Abstract (Invited)

Measurement of Rayleigh Streaming in High-Amplitude Standing Waves

A.A.Atchley, M.W.Thompson (Graduate Program in Acoustics, The Pennsylvania State University, State College, PA, USA)

e-mail: atchley@psu.edu

This investigation is motivated by the desire to better understand Rayleigh streaming in thermoacoustic engines. While searches of archived literature have yielded many theoretical analyses of Rayleigh streaming, surprisingly few experimental investigations have been found. Furthermore, none of the experimental works found contain a thorough, quantitative comparison to theory in the parameter ranges of greatest interest. It has been pointed out [see for example, Menguy and Gilbert, Acustica 86, 249-259 (2000)] that nonlinear effects due to fluid inertia must be taken into account for streaming velocities as small as a few mm/s in ducts having diameters on the order of 1 cm, and in sound fields with frequencies and sound levels on the order of 1 kHz and 145 dB, respectively. We present laser Doppler anemometry measurements of Rayleigh streaming is cylindrical pipes for a range of Reynolds numbers and ratios of pipe radius to wavelength. The measured streaming velocities outside the boundary layer agree reasonable well with classical (i.e., slow streaming) theoretical predictions when the pipe is driven at low amplitudes. However, they deviate significantly from such predictions when the tube is driven at high amplitudes, as suggested by theories of nonlinear acoustic streaming. [Work supported by the Office of Naval Research.]

Section : 7