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Abstract

For more than one hundred years, scientists are working to uncover how turbulent flows occur. This would enable them among others to predict how pollutants spread in water or how pollen travel in air. As EBERHARD BODENSCHATZ explains in this video, new insides are offered by an approach based on Lagrangian Particle Tracking Technique: The researchers focused on a single particle in a fluid and followed it through the flow, both numerically and experimentally using tracers. By tracking more than three thousand particles at a given time, the researchers derived statistics of the particle motion in the flow. This way, they are able to predict turbulences in the flow and prove that these turbulences are irreversible. This irreversibility, in turn, shows that vortex stretching is really at the basis of a turbulent flow.