When intestinal villi generate their own fluid flows

The objective was to determine whether these microscopic structures play a purely passive role in absorption, or whether they can instead actively contribute to the generation of fluid flows.

Inspired by the pendular contraction waves observed in the small intestine, the researchers simulated a channel lined with villi subjected to out-of-phase oscillations. The study, published in the Journal of Fluid Mechanics, shows that these movements create a contraction wave propagating between the villi and inducing a complex fluid flow. The simulations reveal the formation of a mixing layer above the villi, as well as the emergence of a mean flow oriented opposite to the direction of wave propagation — a surprising behavior compared with classical peristaltic flows.

These results illustrate how microscopic geometry and local dynamics can profoundly modify exchanges at the mucosa–lumen interface. They open new perspectives for a better understanding of intestinal transport and for the design of biomimetic devices inspired by the digestive tract.