  Modelling the vascular transport and adhesion of man-made particles is
crucial for optimizing their efficacy in the detection and treatment of
diseases. Here, a Lattice Boltzmann and Immersed Boundary methods are combined
together for predicting the near wall dynamics of particles with different
shapes in a laminar flow. For the lattice Boltzmann modelling, a Gauss-Hermite
projection is used to derive the lattice equation, wall boundary conditions are
imposed through the Zou-He framework, and a moving least squares algorithm
accurately reconstructs the forcing term accounting for the immersed boundary.
First, the computational code is validated against two well-known test cases:
the sedimentation of circular and elliptical cylinders in a quiescent fluid. A
very good agreement is observed between the present results and those available
in the literature. Then, the transport of circular, elliptical, rectangular,
square and triangular particles is analyzed in a Couette flow, at Re=20. All
particles drifted laterally across the stream lines reaching an equilibrium
position, independently of the initial conditions. For this large Reynolds
number, the particle shape has no significant effect on the final equilibrium
position but it does affect the absolute value and periodicity of the angular
velocity. Specifically, elongated particles show longer oscillation periods
and, most interestingly, larger variations in angular velocity. The longest
particles exhibit a zero angular velocity for almost the whole rotational
period. Collectively, this data demonstrates that the proposed approach can be
efficiently used for predicting complex particle dynamics in biologically
relevant flows. This computational strategy could have significant impact in
the field of computational nanomedicine for optimizing the specific delivery of
therapeutic and imaging agents.
