Drag Reduction in Aqueous Flow Systems

Abstract

<p>This thesis presents an experimental study of the drag reduction effects obtained from injecting additive solutions into a turbulent boundary layer developing over a flat plate submerged in water. Both direct injection, from a reservoir through a slit adjacent to the flat plate test section, and ablative coating methods of introducing the additive were studied.</p> <p>Drag reduction data were obtained for polymeric and micelle materials. The test conditions included varying the free stream velocity over the plate from 1.9 to 5.4 fps and injecting the additives in concentrations of up to 2000 wppm at rates up to 50 ml/sec over the test section of the flat plate.</p> <p>It was found that although optimal injection rates exist, drag reduction seems to be a function of how much additive is present in the flow over a test surface and not how it was delivered there. It was also found that ablative coatings of the type used for these experiments seem to have a long life expectancy and produce noticeable drag reduction.</p>