Articles | Volume 22, issue 5
https://doi.org/10.5194/npg-22-571-2015
https://doi.org/10.5194/npg-22-571-2015
Brief communication
 | 
05 Oct 2015
Brief communication |  | 05 Oct 2015

A method to calculate finite-time Lyapunov exponents for inertial particles in incompressible flows

D. Garaboa-Paz and V. Pérez-Muñuzuri

Abstract. The present study aims to improve the calculus of finite-time Lyapunov exponents (FTLEs) applied to describe the transport of inertial particles in a fluid flow. To this aim, the deformation tensor is modified to take into account that the stretching rate between particles separated by a certain distance is influenced by the initial velocity of the particles. Thus, the inertial FTLEs (iFTLEs) are defined in terms of the maximum stretching between infinitesimally close trajectories that have different initial velocities. The advantages of this improvement, if compared to the standard method (Shadden et al., 2005), are discussed for the double-gyre flow and the meandering jet flow. The new method allows one to identify the initial velocity that inertial particles must have in order to maximize their dispersion.

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Short summary
The present study aims to improve the calculus of finite-time Lyapunov exponents (FTLEs) applied to describe the transport of inertial particles in a fluid flow. To this aim, the deformation tensor is modified to take into account that the stretching rate between particles separated by a certain distance is influenced by the initial velocity of the particles. Results are presented for two different flows and compared with the classical method by Shadden (2005).