Prediction of turbulent channel flow with superhydrophobic walls consisting of micro-ribs and cavities oriented parallel to the flow direction

Turbulent flow in a parallel-plate micro-channel with superhydrophobic walls has been explored numerically. The k-omega turbulence model is used for closure to the turbulent Reynolds-averaged Navier-Stokes equations and the Reynolds number was varied from 4 x 10(3) to 10(4). Results show that as the shear-free region increases the apparent velocity slip increases, and the Darcy friction factor decreases. The observed reduction in fraction factor was found to be significantly greater for turbulent flow conditions than for laminar flow scenarios under the same geometric channel conditions. Expressions that correlate the friction factor and apparent slip velocity as functions of the relevant parameters are also presented. (C) 2009 Elsevier Ltd. All rights reserved.