A parametric study on drag reduction using engineered microtextures in viscous laminar flow

Friction reduction has been studied over years for many engineering applications that involve internal and external flows. Inspired by the natural surface structure of different creatures, engineered microtexturing of surfaces is one of the effective ways to reduce the drag. By introducing texture geometries, the flow behavior close to the wall can be manipulated towards achieving a reduced net drag force on the surface. Most works have focused on optimizing the surface texturing for reducing the friction and minimizing the pumping power requirements, while less attention has been paid to characterizing the flow and boundary layer near the wall, especially in laminar regime. We study the role of microtexturing on flow behavior under low to moderate Re. We numerically study the configuration of the textures and investigate the boundary layer and streamline behavior as well as the local shear stress distribution along the solid-fluid interface under different wetting states and flow conditions. The outcomes of this work will provide a guideline for optimal design of artificial textures with major implications for many engineering applications such as microfluidic systems used in thermal management and biochemical diagnostics.