Chaotic advection in a cavity flow with rigid particles

The effect of freely suspended rigid particles on chaotic material transport in a two-dimensional cavity flow is studied. We concentrate on the understanding of the mechanism how the presence of a particle affects the dynamical system of the flow. In contrast to the case studied by Vikhansky ["Chaotic advection of finite-single bodies in a cavity flow," Phys. Fluids 15, 1830 (2003)], we show that even a regular periodic motion of a single particle can induce chaotic advection around the particle. as a result of the perturbation of the flow introduced by the freely rotating solid particle. This perturbation is of a hyperbolic nature. In fact, stretching and folding of the fluid elements are C Guaranteed by the occurrence of the hyperbolic flow perturbation centered at the particle and by the rotation of the freely suspended particle, respectively. The fluid-solid flow problem has been solved by a fictitious-domain/finite-element method based oil a rigid-ring description of the solid particle. A single-particle system is studied in detail in view of the dynamical systems theory and then extended to two- and three-particle systems. (C) 2005 American Institute of physics.