Contributed by the Fluids Engineering Division for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received by the Fluids Engineering Division January 13, 2003; revised manuscript received July 27, 2004. Review conducted by: M. Plesniak.
Drag reduction in turbulent flow, by low concentrations of polymers, is well known since the publication on the phenomenon by Toms 1. Recently, biodegradable surface active agents (surfactants) have become a more appropriate choice as drag reducing additives. These surfactants are environmental friendly and, in addition, they are less susceptible to mechanical degradation 2. The influence on turbulent flow characteristics could be spectacular with only few parts per million of surfactant solution, added to the solvent 3,4. The general belief is that surfactants, like other additives, act directly on the small turbulent scales (4,5 6 and references therein).
The drag reduction effect is due to the...
