Solid
Particle Self-assembly in Time-Periodic Flows:
new Concepts
to Manipulate Matter on Small Scales
Marcello Lappa, Paolo Capobianchi and Balagopal
Manayil Santhosh
Department of Mechanical and Aerospace
Engineering, University of Strathclyde, James Weir Building, 75 Montrose
Street, Glasgow, G1 1XJ, UK
*corresponding author email: marcello.lappa@strath.ac.uk
Application-driven technological
demands require vastly superior control of particles and other inclusions
dispersed in many inorganic and organic materials when they are in the liquid
state. We present a survey of recently discovered mechanisms for solid particle
self-assembly, ordering and accumulation in non-isothermal laminar
time-periodic fluid flows, potentially inherent to exerting such a control. Assuming
surface-tension gradients and vibrational effects as the main mechanisms
driving fluid flow, an attempt is made to disentangle the complex hierarchy of
relationships existing between the multiplicity of the loci of particle aggregation,
the geometry of the physical domain hosting the considered fluid-particle
mixture, the physical properties of the particles per se and the applied
thermal boundary conditions. We show that the particle self-organization processes in time-periodic thermal flows obey
a complex logic, which makes the arrangement of particles different from
realization to realization. As some influential conditions or parameters are
varied, particles can be gradually transferred from the region of influence of
an attractor to another. Moreover, ranges exist where these attractee compete
resulting in overlapping or intertwined particle structures. The final
objective is the integration of new physics in already existing theories and
forge a new unified concept for the (contactless) manipulation of solid matter
dispersed in a fluid, which may lead in the future to alloys with improved
properties or perhaps completely new materials.