Highly shear-thinning fluids are best for nutrient transport in small intestine

If you consider the intricate network inside a human body, you will probably realize many of the functions involve fluid flowing through tubes – blood flows in veins, food and liquids in the throat and esophagus, fluid transport in the intestines. For this reason, the study of how fluid flows in collapsible elastic tubes is important in biomedical fields and biofluid mechanical understandings. Nahar et al. investigated the interaction between an elastic tube’s wall motion and the way liquid moves through it to deepen understanding of tube deformation as it relates to fluid flow.

“Our study shows that the fluid behavior, both Newtonian and non-Newtonian, significantly influences the tube deformation and, consequently, the flow behavior at constant external pressure,” said author Bipro Dubey.

Highly shear-thinning fluids experience a dramatic decrease in viscosity under external pressure. In the small-intestine, fluids transport nutrients into the blood stream through a wall membrane under peristaltic motion, or contraction and relaxation – analogous to a deformed tube. The team found that more highly shear-thinning fluids caused the greatest tube deformation and so should be considered for most efficient nutrient transport.

“Fluid nature impacts tube deformation and flow behavior, which causes an alteration of wall shear stress and viscosity of a shear-thinning fluid,” said Dubey. “Therefore, the nutritional transport through the small-intestinal wall will be influenced by fluid behavior, which can be determined by an appropriate food formulation.”

Dubey believes these findings will spawn further work on how peristalsis impacts fluid transportation.

Source: “Influence of flowing fluid property through an elastic tube on various deformation along the tube length,” by Samsun Nahar, Bipro N. Dubey, and Erich J. Windhab, Physics of Fluids (2019). The article be accessed at https://doi.org/10.1063/1.5123182 .