Drag reduction in polymer solutions based on splash visualization

The drag-reduction phenomenon is produced when very small amounts of some substances such as high-molar-mass polymers are dissolved in a solvent. In this paper some aspects of drag reduction were studied through the observation of the liquid deformation due to the impact of a droplet against a shallow surface using aqueous solutions of poly(ethylene oxide). The presence of polymer leads to a change in the splash morphology, mainly for the Rayleigh jet. The amplitude of the Rayleigh jet is highly sensitive to the concentration and molar mass of the polymer and can be used to determine the percentage of the drag reduction.