Turbulent Boundary Layer Flow Over Superhydrophobic Surfaces

The objective of this project was to determine whether drag caused by turbulence in boundary layer flow can be reduced through the use of modified surfaces. This study encompassed the testing of four different surfaces: 1) Teflon SLIP, 2) Aluminum SLIP, 3) Honeycomb Superhydrophobic and 4) Polydimethylsiloxane elastomer (PDMSe) Superhydrophobic. Each of these surfaces uses specific geometrical surface features to modify the original water-surface interface. Due to the influence of the Green Fleet Initiative and the Navy's goal to increase the fleet efficiency, the Office of Naval Research is interested in determining the effectiveness of these surfaces in boundary layer flow under operating conditions similar to those in which Navy ships operate. The goal of this study was to provide data and analysis detailing the effect of these surfaces on boundary layer turbulence and drag reduction. The performance of each surface was compared with that of a smooth wall under similar operating conditions to characterize the effectiveness of each modified surface.