Drag Coefficients for Spheres in High Reynolds Number Flow of Dilute Solutions of High Polymers

Abstract

DILUTE polymer solutions show substantial reduction of drag in turbulent pipe flow1 and a 28 per cent reduction has been reported for sphere drag coefficients in a 0.5 per cent solution of Guar gum for a 1 in. diameter steel ball2. These drag coefficients were measured by timing balls falling down a 3 in. tube. Greater reductions of sphere friction factors were noted in my recent experiments. Balls were dropped by hand in a glass fronted tank, 1 ft. square and 6 ft. deep. The terminal velocity was found using a photographic technique3 in which the position of the ball every 0.04 sec was recorded on a 35 mm negative.