Concepts and tools from network theory, the so-called Lagrangian Flow Network
framework, have been successfully used to obtain a coarse-grained description
of transport by closed fluid flows. Here we explore the application of this
methodology to open chaotic flows, and check it with numerical results for a
model open flow, namely a jet with a localized wave perturbation. We find that
network nodes with high values of out-degree and of finite-time entropy in the
forward-in-time direction identify the location of the chaotic saddle and its
stable manifold, whereas nodes with high in-degree and backwards finite-time
entropy highlight the location of the saddle and its unstable manifold. The
cyclic clustering coefficient, associated to the presence of periodic orbits,
takes non-vanishing values at the location of the saddle itself.Comment: 7 pages, 3 figures. To appear in European Physical Journal Special
Topics, Topical Issue on "Recent Advances in Nonlinear Dynamics and Complex
Structures: Fundamentals and Applications
