Accession Number : AD0684881

Title :   THE MOTION OF BUBBLES IN A STATIONARY SOUND FIELD.

Descriptive Note : Technical memo.,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS ACOUSTICS RESEARCH LAB

Personal Author(s) : Crum,Lawrence A. ; Eller,Anthony I.

Report Date : JAN 1969

Pagination or Media Count : 93

Abstract : The subject of this report is the motion of an air bubble that is propelled through a liquid by a standing acoustic wave. Values are presented for the translational velocities at which bubbles smaller than resonance size move through the sound field. Bubbles were observed in water and in isopropyl alcohol. Bubble radii ranged from 29 to 149 micrometers, and acoustic pressure amplitudes ranged up to 1.1 bar. The resulting bubble velocities, ranging to 23 cm/sec, were measured by photographing a moving bubble under stroboscopic illumination. Calculated and observed values of the bubble velocity are in agreement as long as the bubble translation is rectilinear. Experimental results also indicate that the bubble translation becomes erratic when the pressure amplitude exceeds a threshold value. This threshold appears to be identical to the threshold, determined in a separate experiment, for the onset of dancing motion of stationary bubbles trapped in a sound field. The results of theoretical calculations suggest that both the erratic translation and the dancing motion are caused by nonspherical oscillations of the bubble that are parametrically excited when the pressure amplitude exceeds a threshold value. (Author)

Descriptors :   (*UNDERWATER SOUND, BUBBLES), STABILITY, MOTION, WATER, ALCOHOLS, VELOCITY

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE