CHARACTERIZATION OF TURBULENT DRAG REDUCTION IN ROTATING-DISK SYSTEM

Turbulent drag reduction in a rotating disk apparatus was characterize d for a homologous series of polyethylene oxide (PEO) polymers coverin g a wide range of molecular weights. The concentration dependence of d rag reduction in this system was shown to obey an empirical drag reduc tion equation which had been previously established by Virk et al. for flows in capillary tubes. The linear correlation between polymer conc entration and C/DR for different molecular weights of PEO was also obt ained. In addition, [C], defined as a characteristic intrinsic concent ration, was found to be extremely useful in normalizing the drag reduc tion data in one homologous series of PEO.