Flow visualizations are presented for acoustic streaming occurring inside spherical elastic cavities oscillating in an acoustic field. Streaming flows are visualized using Particle Image Velocimetry (PIV) and results are observed for a range of values of a dimensionless frequency parameter, M =120-306. Over the frequency range investigated, streaming flow fields remain steady at a given value o...

A numerical investigation was carried out in order to predict the effects of symmetric heating on irregular acoustic streaming in air-filled shallow enclosures. The fluid motion is driven by periodic vibration of the enclosure left wall. The vertical walls of the enclosure are adiabatic while the horizontal walls are heated symmetrically. A control-volume method based, explicit time-marching Fl...

Sir James Lighthill proposed in 1992 that acoustic streaming occurs in the inner ear, as part of the cochlear amplifier mechanism. Here we hypothesize that some of the most ancient organisms use acoustic streaming not only for self-propulsion but also to enhance their nutrient uptake. We focus on a motile strain of Synechococcus, a cyanobacteria whose mechanism for self-propulsion is not known....

This study is a linear stability analysis of the flows induced by ultrasound acoustic waves (Eckart streaming) within an infinite horizontal fluid layer heated from below. We first investigate the dependence of the instability threshold on the normalized acoustic beam width H(b) for an isothermal fluid layer. The critical curve, given by the critical values of the acoustic streaming parameter, ...

Five eigenvectors of the linear thermoviscous flow over the homogeneous background derived for the quasi-plane geometry of the flow. The corresponding projectors are calculated and applied to get the nonlinear evolution equations for the interacting vortical and acoustic modes. Equation on streaming cased by arbitrary acoustic wave is specified. The correspondence to the known results on stream...

Based on first- and second-order perturbation theory, we present a numerical study of the temporal buildup and decay of unsteady acoustic fields and acoustic streaming flows actuated by vibrating walls in the transverse cross-sectional plane of a long straight microchannel under adiabatic conditions and assuming temperature-independent material parameters. The unsteady streaming flow is obtaine...

We report an experimental and numerical characterization of three-dimensional acoustic streaming behavior in small droplets of volumes (1-30 μl) induced by surface acoustic wave (SAW). We provide a quantitative evidence of the existence of strong nonlinear nature of the flow inertia in this SAW-driven flow over a range of the newly defined acoustic parameter F{NA}=Fλ/(σ/R_{d})≥0.01, which is a ...