Understanding the Flow Structure of Low Reynolds Number Flows

We consider a variety of low Reynolds number experimental flows including a Stokes multi-gyre flow and a four roll mill. An investigation of the underlying Lagrangian Coherent Structures (LCS) is performed using images of passive tracer (dye) and with finite-time Lyapunov exponent (FTLE) fields computed via particle imaging velocimetry (PIV). In addition we consider the dynamics of inertial particles in these flows along with the associated inertial LCS for these particle. Results are confirmed with theoretical/numerical models and provide improved understanding of transport in these fluid flows.