Turbulent drag reduction characteristics induced by calf-thymus DNA

We report novel turbulent drag reduction (DR) behaviors of polydisperse calf-thymus DNA (CT-DNA) as a potential drag reducing candidate, by injecting appropriately prepared concentrated stock solution of the CT-DNA into a buffer solution in a rotating disk apparatus. By putting emphasis on the effect of DNA concentration, its DR characteristics were compared with that of λ-DNA possessing monodisperse molecular weight characteristics based on both DR efficiency and a mechanical degradation under turbulence. The DNA chains having much higher molecular size than that of λ-DNA are observed to be more susceptible to mechanical degradation in a turbulent flow. This result was verified via electrophoresis.