The Relationship of Drag Reduction to the Transient Laminar Shear Flow Properties of Polymer Solutions.
NAVAL RESEARCH LAB WASHINGTON D C
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The laminar flow of a polymer solution near a flat plate of infinite extent was investigated theoretically for three cases a the plate is impulsively started and moves in its own plane with a constant velocity b the plate executes linear harmonic oscillations in its own plane c motion of the plate in this plane is a random function of time. By combining the results with a simple model for turbulent flow near a wall, a number of experimentally observed characteristics of the drag reduction phenomenon are predicted. The merits of this transient shear explanation of drag reduction were compared to those of previously offered hypotheses. Some justification was found for expecting the transient shear flow mechanism to be dominant at large flow rates. Author
- Fluid Mechanics