title: 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 corotating vortices. For larger Reynolds number these vortices become isolated, by suppressing fluid transport in the transverse direction.
authors: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119991 Moscow, Russia.
authors: Tatiana V
authors: TV
authors: Nizkaya
authors: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119991 Moscow, Russia.|Central Aero-Hydrodynamic Institute, 140180 Zhukovsky, Moscow region, Russia.
authors: Evgeny S
authors: ES
authors: Asmolov
authors: Institut für Physik, Johannes Gutenberg-Universität Mainz, D55099 Mainz, Germany.
authors: Jiajia
authors: J
authors: Zhou
authors: Institut für Physik, Johannes Gutenberg-Universität Mainz, D55099 Mainz, Germany.
authors: Friederike
authors: F
authors: Schmid
authors: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, 31 Leninsky Prospect, 119991 Moscow, Russia.|Department of Physics, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia.|DWI-Leibniz Institute for Interactive Materials, RWTH Aachen, Forckenbeckstrasse 50, 52056 Aachen, Germany.
authors: Olga I
authors: OI
authors: Vinogradova