Experimentelle Untersuchung turbulenter Rohrströmungen hochreiner wäßriger Polyacrylamid-Lösungen

The polymeric material investigated consisted of laboratory synthesized polyacrylamide molecular weight fractions of relatively low dispersity. Drag reduction measurements were performed in a single pass pipe flow system. A Deborah numberDe and an expression for the drag reductionWV ^* were derived from the hypothesis that the Toms effect results from an increase in the elongational viscosity which reduces the number and the intensity of bursting periods. Figures presentingWV ^* as a function ofDe are shown.