Drag Reduction and Shear Degradation of Dilute Polymer Solutions as Measured by a Rotating Disk
Author: T. T. Huang
Publisher:
Published: 1972
Total Pages: 26
ISBN-13:
DOWNLOAD EBOOKA saturated drag-reduction line for dilute polymer solutions is derived for a rotating disk from new velocity-similarity laws. Drag reduction measured by a rotating disk is found to have three domains--oversaturated, optimal and undersaturated. At a given boundary-layer thickness and wall-shear stress, the drag-reduction increases with increasing concentration in the undersaturated domain, and the drag reduction does not increase with increasing concentration in the oversaturated domain. The boundary between the two domains is the optimal drag reduction, which is determined by the type of polymer and its concentration and a Reynolds number based on shear velocity and disk radius or boundary-layer thickness. (Author).