Extraction of Coherent Structures from Natural and Actuated Flows

We present feature-extraction techniques for numerical and experimental data of complex fluid flows. Focus is placed on efficient analysis and visualization of coherent structures of snapshots, temporal evolution and parameter-dependency of coherent structures. One key enabler are Galilean invariant flow quantities based on pressure, acceleration, vorticity and velocity Jacobians. Other important catalyzers are Lagrangian filters that distill persistent strong particle-fixed features while neglecting weak and short-living ones. The proposed feature extraction framework is exemplified for the time-dependent natural and actuated flow around a high-lift airfoil, as well as other benchmark configurations of the SFB 557.