Flows and mixing in channels with misaligned superhydrophobic walls

Abstract

Aligned superhydrophobic surfaces with the same texture orientation reduce drag in the channel and generate secondary flows transverse to the direction of the applied pressure gradient. Here we show that a transverse shear can be easily generated by using superhydrophobic channels with misaligned textured surfaces. We propose a general theoretical approach to quantify this transverse flow by introducing the concept of an effective shear tensor. To illustrate its use, we present approximate theoretical solutions and Dissipative Particle Dynamics simulations for striped superhydrophobic channels. Our results demonstrate that the transverse shear leads to complex flow patterns, which provide a new mechanism of a passive vertical mixing at the scale of a texture period. Depending on the value of Reynolds number two different scenarios occur. At relatively low Reynolds number the flow represents a transverse shear superimposed with two co-rotating vortices. For larger Reynolds number these vortices become isolated, by suppressing fluid transport in the transverse direction.

8 pages, 10 figures

References in corpus (5)

• Geometric transition in friction for flow over a bubble mattress
• Effective slip over superhydrophobic surfaces in thin channels
• Direct measurements of hydrophobic slippage using double-focus fluorescence cross-correlation
• Tunable-slip boundaries for coarse-grained simulations of fluid flow
• 'Gas cushion' model and hydrodynamic boundary conditions for superhydrophobic textures

Cited by in corpus (5)

• Speed limit to the Abrikosov lattice in mesoscopic superconductors
• Inertial migration of neutrally-buoyant particles in superhydrophobic channels
• Regimes of Wetting Transitions on Superhydrophobic Textures Conditioned by Energy of Receding Contact Lines
• Advective superdiffusion in superhydrophobic microchannels
• Hydrodynamics of flagellated microswimmers near free-slip interfaces