Steady streaming flow induced by active biological microstructures; application to small intestine villi

Physiological transport of fluid at small scales is often achieved by microscopic active fingerlike structures. It recognized that they have to move in a non-symmetric fashion order break the symmetry creeping flow and induce net movement fluid. However, limit low, but non-vanishing, Reynolds number, irreversible on long time could also be generated symmetric oscillations these microstructures. Inspired intestine villi, we reported three dimensional direct numerical simulations part flow, namely steady streaming (SSF), an array oscillating In capture second phenomena, algorithm was based combination lattice-Boltzmann methods with two relaxation times smoothed profile method. SSF confined inside viscous boundary above villi. Two vortices tip villi characterized this which induced mass transfers between bulk periphery. Strikingly, spatial extension not solely governed Stokes layer lateral confinement Moreover, secondary outside were observed. These findings rationalized state diagram showing regimes SSF. Finally, orders magnitude showed should contribute particles, such as bacteria or nano-particles, few hundred micrometers scale minutes.