Stability of laminar pipe flows of drag reducing polymer solutions in the presence of high‐phase‐velocity disturbances

A theoretical study of high‐phase‐velocity disturbances in the laminar pipe flow of drag‐reducing polymer solutions is reported. These disturbances are found to be more stable in a polymer solution with a sufficiently small relaxation time than in a Newtonian fluid. The opposite effect is predicted when the relaxation time exceeds a critical value, however. These results are shown to be consistent with a hydrodynamic instability explanation of the early turbulence phenomenon.