Turbulent Submerged Jets of Dilute Polymer Solutions

Dilute synthetic polymer solutions have been shown to reduce turbulent drag in pipelines and around marine vehicles. Water-soluble biopolymers such as flax seed mucilage extracts have the potential to serve as cheap and environmentally friendly alternatives to synthetic polymers. In this work, we employ Schlieren imaging to unveil the mixing dynamics and recirculating regions that develop in turbulent jets of dilute aqueous polymer solutions submerged in quiescent water. At the interface of the viscoelastic jet and water, a free shear boundary layer develops leading to momentum transfer between the two fluids. We demonstrate the impact of viscoelasticity on this momentum transfer and evaluate the performance of both synthetic polymers and biopolymers in damping turbulent vortical structures.