Acoustic radiation- and streaming-induced microparticle velocities determined by microparticle image velocimetry in an ultrasound symmetry plane
Acoustic radiation- and streaming-induced microparticle velocities determined by microparticle image velocimetry in an ultrasound symmetry plane
复制标题
DOI：
10.1103/physreve.86.056307
复制
发表时间：
2012-11-13
影响因子：
2.4
通讯作者：
Bruus, Henrik
中科院分区：
文献类型：
--
作者：
Barnkob, Rune;Augustsson, Per;Bruus, Henrik
用微粒子图像测速仪测量了微通道中超声对称面中直径为0.6~10微米的悬浮微粒的声阻抗特性。最小颗粒的运动主要受诱导声流的斯托克斯阻力的影响，而最大颗粒的运动主要受声辐射力的影响。对于所有颗粒大小，我们分别从理论上预测了有多少颗粒速度是由辐射和流动引起的。这些预测包括对颗粒-壁相互作用和超声热粘性效应的修正，并在实验不确定度范围内与我们的测量结果相匹配。最后，我们从理论上预测并实验证实了声辐射和流动诱导的颗粒速度之比与激励频率、声学对比度和颗粒尺寸的平方成正比，而与运动粘度成反比。
We present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10 mu m undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel. The motion of the smallest particles is dominated by the Stokes drag from the induced acoustic streaming flow, while the motion of the largest particles is dominated by the acoustic radiation force. For all particle sizes we predict theoretically how much of the particle velocity is due to radiation and streaming, respectively. These predictions include corrections for particle-wall interactions and ultrasonic thermoviscous effects and match our measurements within the experimental uncertainty. Finally, we predict theoretically and confirm experimentally that the ratio between the acoustic radiation-and streaming-induced particle velocities is proportional to the actuation frequency, the acoustic contrast factor, and the square of the particle size, while it is inversely proportional to the kinematic viscosity.