论文标题
揭示由尖锐边缘引起的声流的机制
Unveiling of the mechanisms of acoustic streaming induced by sharp edges
论文作者
论文摘要
由于构成典型的厚度$δ$的粘性边界层的产生，声波会在流体中产生稳定的流动流。在微通道中，调整了声学波长$λ$，以确保通道宽度$ W $的两倍以确保共振条件，这意味着使用MHz传感器。但是最近，由于存在小于$Δ$的尖端$ r_c $，曲线半径尖锐的结构，这是由几个kHz的声波（因此具有$λ\ gg w $）产生的强烈声流。本研究使用有限元方法定量研究了通过完整的Navier-Stokes方程的直接分辨率来研究这种尖锐的声学流。 $δ$，$ r_c $和粘度$ν$对声流性能的影响是量化的。我们的结果表明，通过无量纲数量$ r_c/δ$和$δ/w $选择操作条件和几何参数，并提供了有关如何获得强大，最佳尖锐的声学流的指南。
Acoustic waves can generate steady streaming within a fluid owing to the generation of viscous boundary layers near walls, of typical thickness $δ$. In microchannels, the acoustic wavelength $λ$ is adjusted to twice the channel width $w$ to ensure a resonance condition, which implies the use of MHz transducers. Recently though, intense acoustic streaming was generated by acoustic waves of a few kHz (hence with $λ\gg w$), owing to the presence of sharp-tipped structures of curvature radius at the tip $r_c$ smaller than $δ$. The present study quantitatively investigates this sharp-edge acoustic streaming via the direct resolution of the full Navier-Stokes equation, using Finite Element Method. The influence of $δ$, $r_c$ and viscosity $ν$ on the acoustic streaming performance are quantified. Our results suggest choices of operating conditions and geometrical parameters, via dimensionless quantities $r_c/δ$ and $δ/w$ and provide guidelines on how to obtain strong, optimal sharp-edge acoustic streaming.
