Slip flow over structured surfaces with entrapped microbubbles

Abstract

On hydrophobic surfaces, roughness may lead to a transition to a superhydrophobic state, where gas bubbles at the surface can have a strong impact on a detected slip. We present two-phase lattice Boltzmann simulations of a Couette flow over structured surfaces with attached gas bubbles. Even though the bubbles add slippery surfaces to the channel, they can cause negative slip to appear due to the increased roughness. The simulation method used allows the bubbles to deform due to viscous stresses. We find a decrease of the detected slip with increasing shear rate which is in contrast to some recent experimental results implicating that bubble deformation cannot account for these experiments. Possible applications of bubble surfaces in microfluidic devices are discussed.

4 pages, 4 figures. v2: revised version, to appear in Phys. Rev. Lett

References in corpus (4)

• Slippage of water past superhydrophobic carbon nanotube forests in microchannels
• Mesoscopic modeling of a two-phase flow in the presence of boundaries: the Contact Angle
• Roughness induced boundary slip in microchannel flows
• Lattice Boltzmann simulations of apparent slip in hydrophobic microchannels

Cited by in corpus (4)

• Geometric transition in friction for flow over a bubble mattress
• Effective slip over superhydrophobic surfaces in thin channels
• Lattice Boltzmann simulations in microfluidics: probing the no-slip boundary condition in hydrophobic, rough, and surface nanobubble laden microchannels
• A boundary condition with adjustable slip length for Lattice Boltzmann simulations