The drag reduction effects of a non-Newtonian fluid (CMC aqueous solution) in a sinusoidal wavy-walled tube at moderate Reynolds numbers for steady flow

Abstract

Abstract. The drag reduction effects of a non-Newtonian fluid (CMC aqueous solution with 50-1000wppm) in a sinusoidal wavy-walled tube were investigated experimentally in the Reynolds numbers range from 25 to 360. Based on the pressure drop method, drag reduction was measured and the maximum drag reduction achieved was 38% using 700wppm. It was found that in the end of the laminar flow region the CMC polymer solutions display more distinct drag reduction than that in turbulent flow region. Besides, the effect of rheological parameters on drag reduction has been discussed.