How do ellipsoidal particles behave dynamically in a high-frequency standing acoustic wave field? Our newest publication in Microfluidics and Nanofluidics addresses this question by comprehensive experimental investigations and reveals the focusing and counterintuitive alignment of the non-spherical particles orthogonal to the pressure nodes (see video). To shed light on the physical mechanisms underlying this alignment, a 3D numerical model was developed that predicts the acoustic force and torque on a particle in excellent agreement with the experimental results. On top of that, a dependence of the acoustic force on the particle shape is found, which paves the way for a shape-dependent particle separation in future acoustofluidic devices with tailored design.

 

The whole study is freely accessible to everyone!

 

We would like to express our particular appreciation to Laura Weirauch from Universität Bremen, who helped providing the ellipsoidal particles, and to David Schreier as well as the team from ZMN, without whom this study would not have been possible. Furthermore, we thank the DFG for funding within the priority program PP2045 "MehrDimPart".