Normal stress measurements on drag-reducing polymer solutions

Summary The elastic properties of very dilute solutions of a number of drag-reducing polymers differing either in chemical nature or molecular weight were investigated over a range of values of shear stress using the jet thrust method. Parallel drag reduction measurements were also made with the solutions. The results indicate a general relationship between the value of the first normal stress difference at the wall, (p₁₁-p₂₂, and the dragreducing ability.The data tends to confirm the generality of the correlation between the value of theWeissenberg number and the drag reduction reported byMetzner for a single polymer sample.