Abstract
Nata de coco suspensions reduced the pressure loss in circular pipe flow, and the effect of the drag reduction strongly depends on mixing time of blender for preparing nata de coco suspension. In this study, with respect to the mechanism of the drag reduction, the relation between viscosity, drag reduction phenomena and fiber form of nata de coco was investigated. We found that the nata de coco suspension has a shear-thinning viscosity. The viscosity fluctuation and the drag reduction were observed for the short mixing time (1.5 and 3 min) of blender. A large network of nata de coco fibers formed in this case. In contrast, the viscosity fluctuation and the drag reduction were not observed in the case of long mixing time (10 min) of blender.
