The frictional drag reduction of high molecular weight poly(ethy1ene oxide) and polystyrene solutions under turbulent flow conditions has been studied as a function of temperature, solvent power, and solvent viscosity. A rotatingdisc apparatus was used to make the drag reduction measurements. For aqueom poly(ethy1ene oxide) solutions, a t concentrations well above that needed to produce maximum drag reduction, all drag reduction data reduced to a common curve when per cent drag reduction was plotted against the Reynolds number for the flow. However, for poly(ethy1ene oxide) solutions below this optimum concentration, the drag reduction-versus-Reynolds number curves showed decreasing drag reduction with increasing temperature. The data are explained primarily in terms of the inverse temperature solubility characteristics of poly(ethy1ene oxide) in water. The per cent drag reduction of polystyrene in nonaqueous liquids was found to be greater in good solvenks than in poor ones. It was also found that increases in solvent viscosity and decreases in temperature increased the per cent drag reduction.
The results are discussed in relation to the current drag reduction theories and are shown to be in opposition to Virk's theory. It is concluded from the data that drag reduction is very likely a function of a relaxation time phenomenon involving the polymer mole cules and the flow system. The results also emphasize the importance of considering solvent power, viscosity, and temperature in the design of an efficient drag reduction system.