English: The internal flow of a fluidic oscillator together with its sweeping jet in the external flow field is captured by particle image velocimetry. The entire flow field is composed of several measurement domains concatenated to a global picture. The oscillatory motion in the individual measurements is inferred from simultaneous pressure measurements. This allows for the construction of a time-resolved flow field of the periodic motion in the internal and external flow. This composite data set enables the calculation of Lagrangian coherent structures (LCS) using finite-time Lyapunov exponents. The representation of the flow with LCS provides an intuitive comprehension of the complex dynamics in this flow. The switching mechanism in the internal flow, as well as the mixing in the external flow, can easily be deduced from this representation. Besides the scientific insight, the animated periodic motion of the flow has a high artistic value. It emphasizes the pure beauty of fluid dynamics phenomena through the combination of state-of-the-art measurement techniques and data processing.

The video was presented at the 2015 gallery of fluid motion, where it was selected as a 2015 APS/DFD Gallery of Fluid Motion Award Winner. [1]

Further details about the experimental setup, the visualization method, and the related research can be found in a corresponding paper. [2]

The original publication can be found on the APS website. [3]