Micro Fibers in Turbulent Open Channel Flow

Fragmentation of big plastic debris, fishing equipment and most importantly wastewater of washing machines and laundry process eventually produce dramatically increasing microfiber pollution in oceans with enormous consequences on the marine environment and food-chain. Photo-degradation, chemical, mechanical and bio-deterioration produce embrittlement of the plastics, which further leads to fragmentation into smaller pieces through wave action. These anisotropic elongated microfibers, with size distribution around 1 mm, can stay afloat on the surface, but can also be transported to deep oceanic regions by settling, drift, turbidity currents and thermohaline circulations. The need for efficient and sustainable remediation solutions is urgent, and it must be based on systematic understanding and modelling of the behaviour of microfibers in the oceans. A free surface, wavy turbulent flow will be experimentally realised in the TU Wien Turbulent Water Channel and dispersion of small plastic fibers will be investigated. Via Laser-optical measurements, three-dimensional, time dependent shape and dynamics of the fibers together with the local turbulent flow features will be recorded and analysed producing a large public database that can be used to calibrate dispersion models for micro-plastic in the free surface oceanic flows.