Sydney Dynamics Group Seminar: Padberg-Gehle (Leuphana Universitat Luneburg) -- From trajectories to transport: network-based approaches for coherent sets and scalar mixing in turbulent flows

Seminar : Sydney Dynamics group Seminar 
Day/time : Thursday, March 5 at 4:00 PM,
Location : SMRI seminar room (A12 Macleay Room 301) 
Speaker : Prof. Kathrin Padberg-Gehle (Leuphana Universitat Luneburg) 

Title: From trajectories to transport: network-based approaches for coherent sets and
scalar mixing in turbulent flows 

Abstract: Understanding, quantifying and controlling transport and mixing processes are 
central in the study of fluid flows.  Many different Lagrangian approaches have been 
proposed for detecting organizing flow structures,
including recent data-based methods that aim to identify such coherent objects directly
from simulated or measured tracer trajectories.  Among these approaches are Lagrangian
flow networks, where trajectories serve as network nodes and the links are weighted
according to spatio-temporal distances between trajectories.  Spectral clustering as
well as simple network measures such as node degrees or clustering coefficients can be
used to identify flow regions of different dynamical behavior.  In this talk, we propose
some extensions to the network-based framework that allow us (i) to study the long-term
dynamics of coherent sets in turbulent flows and (ii) to describe and quantify the
transport and mixing of scalar quantities.  We demonstrate our approaches in a number of
example systems, including turbulent Rayleigh-Bénard convection flows.