Lagrangian coherent structures and inertial particle dynamics

Abstract

In this work we investigate the dynamics of inertial particles using finite-time Lyapunov exponents (FTLE). In particular, we characterize the attractor and repeller structures underlying preferential concentration of inertial particles in terms of FTLE fields of the underlying carrier fluid. Inertial particles that are heavier than the ambient fluid (aerosols) attract onto ridges of the negative-time fluid FTLE. This negative-time FTLE ridge becomes a repeller for particles that are lighter than the carrier fluid (bubbles). We also examine the inertial FTLE (iFTLE) determined by the trajectories of inertial particles evolved using the Maxey-Riley equations with non-zero Stokes number and density ratio. Finally, we explore the low-pass filtering effect of Stokes number. These ideas are demonstrated on two-dimensional numerical simulations of the unsteady double gyre flow.

12 pages, 5 figures

References in corpus (5)

• Heavy particle concentration in turbulence at dissipative and inertial scales
• Lyapunov exponents of heavy particles in turbulence
• Caustics and clustering in the vicinity of a vortex
• Particle separation by Stokes number for small neutrally buoyant spheres in a fluid
• Analysis of the Correlation Dimension for Inertial Particles

Cited by in corpus (6)

• Building a Maxey--Riley framework for surface ocean inertial particle dynamics
• Nonlinear dynamics of inertial particles in the ocean: From drifters and floats to marine debris and Sargassum
• Finite-Horizon, Energy-Optimal Trajectories in Unsteady Flows
• The waltz of tiny droplets and the flow they live in
• Quantifying the role of folding in nonautonomous flows: the unsteady Double-Gyre
• Relevance of the Basset history term for Lagrangian particle dynamics