On the Motion of Inertial Particles in Unsteady Flows

Abstract

Inertial particles transported in unsteady flows will not be able to follow the fluid motion perfectly. We explore some of the effects caused by particle inertia. The dissertation contains three parts. In the first part, we show that ellipsoidal particles rotating in oscillating shear flows can exhibit chaotic rotation, and we investigate how the rotation is affected by particle shape and inertia. The second part outlines a set of numerical simulation tools developed to conduct large scale computational studies of particle motion. This includes both a new direct numerical simulation code and two synthetic turbulence generation tools. In the third part, we use the numerical simulation tools to study particle clustering, the tendency for particles to distribute inhomogeneously in space. We discuss some of the characteristics and mechanisms of clustering in both synthetic homogeneous isotropic turbulence and turbulent channel flows.