Experimental and Computational Studies of Peristaltic Flow in a Duodenal Model

Abstract

We study peristaltic flow in a C-shaped compliant tube representing the first section of the small intestine—the duodenum. A benchtop model comprising of a silicone tube filled with a glycerol-water mixture deformed by a rotating roller was created. Particle image velocimetry (PIV) was used to image flow patterns for deformations approximating conditions in the duodenum (contraction amplitude of 34% and wave speed 13 mm/s). Reversed flow was present underneath the roller with fluid moving opposite to the direction of the peristaltic wave propagation. Deformations of the tube were imaged and used to construct a computational fluid dynamics (CFD) model of flow with moving boundaries. The PIV and CFD vorticity and velocity fields were qualitatively similar. The vorticity field was integrated over the imaging region to compute the total circulation and there was on average a 22% difference in the total circulation between the experimental and numerical results. Higher shear rates were observed with water compared to the higher viscosity fluids. This model is a useful tool to study the effect of digesta properties, anatomical variations, and peristaltic contraction patterns on mixing and transport in the duodenum in health and disease.