An Experimental Study of the Effects of Aqueous Polymer Solutions on a Liquid Boundary Layer

Abstract

<p> This thesis is an experimental study of the effects of injecting dilute polymer solutions into a turbulent boundary layer developed on a flat plate submerged in water.</p> <p> A flat plate having a plexiglass surface together with a separate leading edge piece were specially designed for observing the boundary layer phenomena. Aqueous polymer solutions were introduced into the boundary layer through a slit situated in the leading edge piece. Hot-film anemometer technique was employed in the measurements of velocity profiles, turbulence intensities and lateral correlation coefficients at several locations on the plate. The investigation was carried out for two Reynolds Numbers, based on the length of the plate, of 2.4 x 10^5 and 6.4 x 10^5. The variation in the drag force with respect to the polymer concentrations and the injection rates was assessed based on the velocity profile data. It was found that the momentum diffusivity was smaller than for pure water, and that the presence of the polymer molecules seemed to promote a more uniform distribution of the sizes of the turbulence eddies.</p>