Simulation of elastic filaments interacting with a viscous pulsatile flow

Atherosclerosis is a progressive build-up of plaques (fat-like substances in the blood) on the inner arterial wall. Under certain conditions, the plaque may rupture and plaque fragments may aggregate and cause obstruction downstream. Therefore it is of scientific interest to investigate the interaction of broken plaque fragments in blood flows.

As a first step in attempting to simulate the interaction of ruptured plaque fragments, we use the immersed boundary method to perform simulations of elastic filaments in a 2D incompressible viscous homogeneous Newtonian flow under pulsatile inlet and outlet boundary conditions.

We perform simulations with a single filament and with multiple filaments at various orientations and locations. For a single filament, the results show that irrespective of initial orientation and location, the final orientation of the filament is always perpendicular to the flow and, constitutes a stable position of maximum drag. For a group of two filaments initially in close proximity, they interact in each others wake and separate at the end. Simulation results with many randomly distributed filaments are also discussed.

These preliminary results seem to indicate that fluid-dynamical forces alone do not cause aggregation of ruptured plaque fragments. Some other bio-chemically attractive forces may be needed in order for aggregation to occur.