In this video, we employ Schlieren imaging to enable direct flow visualization of the mixing dynamics and recirculating regions that develop in complex flows of dilute aqueous polymer solutions. With this technique we are able to detect density differences of order 1% for dilute aqueous solutions of polyethylene oxide (PEO) as well as for polysaccharide exudates extracted from the husks of flax seed. This promising visualization capability is used to help understand instabilities in jets of non-Newtonian fluids. In our experiments, the onset of instability and viscous entertainment for turbulent high speed dilute polymer jets is visualized and compared to a jet of Newtonian fluid.
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