SAWLab Saxony, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany.
Lab Chip. 2017 Jun 13;17(12):2104-2114. doi: 10.1039/c7lc00184c.
The characterisation of the fluid motion induced by the acoustic streaming effect is of paramount interest for novel microfluidic devices based on surface acoustic waves (SAWs), e.g. for a detailed description of the achievable mixing efficiency and thus the design of such devices. Here, we present for the first time a quantitative 3D comparison between experimental measurements and numerical simulations of the acoustic streaming induced fluid flow inside a microchannel originating from a SAW. On the one hand, we performed fully three-dimensional velocity measurements using the astigmatism particle tracking velocimetry. On the other hand, we derived a novel streaming force approach solving the damped wave equation, which allows fast and easy 3D simulations of the acoustic streaming induced fluid flow. Furthermore, measurements of the SAW amplitude profile inside the fluid filled microchannel were performed. Based on these results, we obtained a very good agreement between the velocity measurements and the simulations of the fluid flow demonstrating the importance of comprising the actual shape of the SAW amplitude profile for quantitatively reliable simulations. It is shown that the novel streaming force approach is a valid approximation for the simulation of the acoustic streaming induced fluid flow, allowing a rapid and simple estimation of the flow field of SAW based microfluidic devices.
对基于表面声波（SAW）的新型微流控器件而言，声流效应所引起的流体运动特性至关重要，例如，声流混合效率的详细描述以及此类器件的设计。在此，我们首次对源于 SAW 的微通道内的声流诱导的流体流动进行了实验测量和数值模拟的定量三维比较。一方面，我们使用像散粒子跟踪测速法（astigmatism particle tracking velocimetry）进行了完全的三维速度测量。另一方面，我们提出了一种新的流体力方法，该方法求解了阻尼波方程，从而可以快速、轻松地模拟声流诱导的流体流动的三维情况。此外，还对充满流体的微通道内的 SAW 幅度分布进行了测量。基于这些结果，我们在速度测量和流体流动的模拟之间获得了非常好的一致性，证明了考虑 SAW 幅度分布的实际形状对于定量可靠的模拟非常重要。结果表明，新的流体力方法是模拟声流诱导的流体流动的有效近似方法，允许对基于 SAW 的微流控器件的流场进行快速、简单的估计。
