Critical Points in the wake of bio-inspired undulated cylinders

The unique geometry of seal whiskers consisting of a dual set of undulations along their span has been studied for their significant reduction in drag and vortex-induced vibration (VIV) when compared to smooth elliptical cylinders. These reduced forces and vibrations are intricately linked with the three-dimensional vortex formations downstream. This work investigates the wake structure, including its formation and break-up, by labeling and classifying regions of critical points. Critical points describe the flow topology around their neighborhood and are classified to a first-order approximation based on linear properties of the vector field. The effect on three-dimensional wake patterns and wavelength variation are investigated. The objective of this analysis is to perform correlation techniques and analyze the interrelationship between critical points and other flow properties like vorticity, Q-criterion.