The influence of fluid elasticity on the drag coefficient for creeping flow around a sphere

TLDR: In this article, the effect of fluid elasticity on the drag coefficient in the absence of any significant shear-thinning effects is clearly demonstrated, and a continuous reduction in drag below the Stokes value is observed until an asymptotic reduction of 26% is reached for We >/ 0.7.

Abstract: Drag coefficients are measured for the creeping motion of a sphere in nonshear-thinning elastic fluids. The data obtained cover a Weissenberg number range of 1.66 × 10−4 to 2.02. For 0 ⩽ We ⩽ 0.1 no significant deviation from the Stokes drag is observed as a result of fluid elasticity. For We > 0.1 a continuous reduction in drag below the Stokes value is observed until an asymptotic reduction of 26% is reached for We >/ 0.7. Existing theoretical analyses are inadequate for predicting the reduction in drag observed and its asymptotic value. The effect of fluid elasticity on the drag coefficient in the absence of any significant shear-thinning effects is clearly demonstrated.