Drag reduction and structural turbulence in flowing polyox solutions

Abstract

Abstract Structural turbulence has been detected in dilute aqueous solutions of Polyox Coagulant (also known to be a highly effective drag‐reducing agent). The flow line which characterizes structural turbulence from its onset in the laminar region passes well into the fully turbulent region (Reynolds turbulence) with virtually no change in slope, implying that the same molecular oscillations or segmental motions responsible for structural turbulence are now operative in drag reduction. The persistence of structural turbulence at very low concentrations is rationalized on the basis of Busse's explanation of the role of polymer entanglements in viscosity and elastic turbulence.