Acoustophoresis, i.e. the contactless handling of cells, particles and small organisms by means of acoustic waves has received increased attention during the last years and spawned several applications.
Bulk acoustic wave devices exploit the high quality-factors of the acoustic resonances in microfluidic channels with high impedance walls to generate high acoustic pressures and fast acoustophoretic motion. Unfortunately, up to date, most research is limited to a single resonance mode of the bulk acoustic devices. This limitation is artificial and exploiting additional modes would increase the available degrees of freedom drastically. The goal of the underlying study is to investigate theoretically (and numerically) to what extent multi-modal actuation can lead to improved control and versatility of acoustophoresis applications. To this end, the student will model acoustic resonance modes and the induced acoustic force fields for channels of different geometries analytically and using the finite element method.
In a next step, the resulting force fields will be combined with a dynamic trajectory simulation [1,2] to compute the trajectories of individual particles in those resulting force fields. Then an algorithm will be created that selects amplitude and duration of the excited modes to control the path of a single and multiple particles independently.
Knowledge of vibrational systems, Matlab, Mathematica and Comsol is certainly an advantage but not required.
Figure : Rotation of a particle clump by amplitude modulation of two-orthogonal standing waves over the course of 5 seconds. The figure is reproduced from reference . This example shows the potential of multi-modal actuation for the contactless handling of particles and cells in acoustic force fields.
If you are interested in joining this project please contact:
Thierry Baasch at Thierry.Baasch@bme.lth.se.
The project is carried out in the biomedical acoustophoresis group of Prof. Thomas Laurell (Thomas.Laurell@bme.lth.se
 Baasch, Thierry, Ivo Leibacher, and Jürg Dual. "Multibody dynamics in acoustophoresis." The Journal of the Acoustical Society of America141.3 (2017): 1664-1674.
 Baasch, Thierry, and Jürg Dual. "Acoustofluidic particle dynamics: Beyond the Rayleigh limit." The Journal of the Acoustical Society of America143.1 (2018): 509-519)