Acoustic Einstein-Hopf Drag on a Bubble

Abstract

Theoretical results show that the drag on a bubble can be modified by the presence of isotropic, homogeneous, broadband acoustic noise, when the band overlaps the bubbleâ s resonance width. While these results constitute an acoustic analog to the Einstein-Hopf drag on an oscillating dipole in the presence of electromagnetic fluctuations, an important difference is that band-limited acoustic noise can reduce the drag when the lower frequency of the spectrum coincides with the resonant frequency of the bubble. Applications to bubble migration, heat transfer, and acoustophoresis are suggested.