Modeling Time-Dependent, Rigid-Body Motion of a Microswimmer

A. F. Tabak [1], G. Amador [1], M. Sitti [1],
[1] Max Planck Institute for Intelligent Systems, Stuttgart, Germany
Published in 2016

The thermocapillary effect is widely used in microfluidic applications for sensing and actuation and can also be used to generate rigid-body motion. Furthermore, it is possible to cast Marangoni flows to achieve controllable rigid-body motion in 3D space. To this effect, here we present the basics of a simulation technique to analyze 6-DOF time-dependent rigid-body motion of such a microswimmer actuated with Marangoni effect. We simulated the time-dependent behavior of the microswimmer and imposed a constant heat input on one half of the swimmer, generating a temperature profile along the surfaces which in turn invoked the thermocapillary flow at the interfaces between trapped air pockets and the surrounding water. Resultant overall flow field generated the necessary thrust in order to move forward. We also observed that with rubber mesh approach and quaternion rotation formulae the total degrees of freedom to solve for reduces considerably (around 70K), hence reducing computational requirements and solution time.