Page 474 - Handbook of Biomechatronics

468 Ahmet Fatih Tabak

Fig. 3 Computational fluid dynamics (CFD) simulation example: a bacteria-like micro-
swimmer swimming in the liquid bulk, depicted with the plane-confined streamlines
of surrounding flow field. Tetrahedral elements are used to mesh the surface of the
micro-swimmer and the entire fluid-domain. Streamlines are found by finite element
method (FEM) solution of Navier-Stokes equations subject to conservation of mass.
The solution is obtained by COMSOL Multiphysics (COMSOL AB, Stockholm, Sweden).

impractical, as the combined geometry of the micro-swimmer and the sur-
rounding boundaries forces induced flow fields to be asymmetric and
intricate.

2.2.3 Importance of Dimensionless Analysis for Robotic Design and
Applications
Before going further deep into design and analysis of micro-swimmers, the
reader should be familiarized with a list of dimensionless numbers.
Envisioned micro-robotic systems, either experimental or numerical, vary
in size and vary in the method of actuation of the end-effector. Furthermore,
the manufacturing methods could present distinct physical properties that
are not common in general. In short, dimensionless numbers are required
to examine, characterize, and compare the micro-robotic systems discussed
in the literature, in terms of hydrodynamics, elasto-hydrodynamics, magne-
tohydrodynamics, and magneto-elastic characteristics, whenever they are
pertinent to the application.
The dimensionless numbers presented here are referred to help
researchers to find the optimum conditions of the micro-swimmers that
are fully submerged in liquids and of the swimming conditions these
micro-swimmers are subject to. Moreover, dimensionless numbers are help-
ful determining the design space in which the optimum will be searched for.
Finally, they allow researchers to study the behavior of such systems with