  Employing acoustofluidic simulations, we study the propulsion of cone-shaped
nano- and microparticles by a traveling ultrasound wave. In particular, we
investigate how the acoustic propulsion of the particles depends on their size
and the energy density and frequency of the ultrasound wave. Our results reveal
that the flow field generated around the particles depends on all three of
these parameters. The results also show that the propulsion velocity of a
particle increases linearly with the particle size and energy density and that
an increase of the sound frequency leads to an increase of the propulsion
velocity for frequencies below about 1 MHz but to a decrease of the propulsion
velocity for larger frequencies. These findings are compared with preliminary
results from the literature.
