A Freeman Scholar Lecture: The Effect of Additives on Fluid Friction

The turbulent frictional resistance of dilute polymer solutions can be as low as one-quarter that of the pure solvent. The reduction of drag can be associated with polymer properties and the hydrodynamics of the flow. This review illustrates the key concepts in hydrodynamics, polymer chemistry, and rheology which apply to polymer drag reduction. The effect of parts-per-million polymer concentrations on laminar-turbulent transition, boundary-layer properties and turbulent frictional resistance in pipe flow and along flat plates is emphasized, using experimental data from current literature. Industrial, fire-fighting, marine, and biological applications are discussed.