title: Drag reduction on a patterned superhydrophobic surface.
abstract: We present an experimental study of a low-Reynolds number shear flow between two surfaces, one of which has a regular grooved texture augmented with a superhydrophobic coating. The combination reduces the effective fluid-surface contact area, thereby appreciably decreasing the drag on the surface and effectively changing the macroscopic boundary condition on the surface from no slip to limited slip. We measure the force on the surface and the velocity field in the immediate vicinity on the surface (and thus the wall shear) simultaneously. The latter facilitates a direct assessment of the effective slip length associated with the drag reduction.
authors.affiliation: Department of Mechanical Engineering, The University of New Mexico, Albuquerque, New Mexico 87131, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Truesdell
authors.forename: Andrea
authors.initials: A
authors.lastname: Mammoli
authors.forename: Peter
authors.initials: P
authors.lastname: Vorobieff
authors.forename: Frank
authors.initials: F
authors.lastname: van Swol
authors.forename: C Jeffrey
authors.initials: CJ
authors.lastname: Brinker