Acoustic propulsion of nano- and microcones: dependence on the viscosity of the surrounding fluid

TL;DR

This study explores how the acoustic propulsion of nano- and microcone particles varies with the surrounding fluid's viscosity, revealing a strong dependence on shear viscosity through computer simulations.

Contribution

It demonstrates the significant influence of shear viscosity on particle propulsion, highlighting the differential effects of shear versus bulk viscosity.

Findings

Propulsion decreases with increasing shear viscosity.

Propulsion can change sign at high shear viscosity.

Weak dependence of propulsion on bulk viscosity.

Abstract

This article investigates how the acoustic propulsion of cone-shaped colloidal particles that are exposed to a traveling ultrasound wave depends on the viscosity of the fluid surrounding the particles. Using acoustofluidic computer simulations, we found that the propulsion of such nano- and microcones decreases strongly and even changes sign for increasing shear viscosity. In contrast, we found only a weak dependence of the propulsion on the bulk viscosity. The obtained results are in line with the findings of previous theoretical and experimental studies.