An experimental analysis of an impedance pump as a model for segmentation in the intestine

Abstract

The intestine is a fluid-filled compliant tube that twists, turns, and folds back on itself, potentially causing changes in impedance of the tube. By asymmetrically compressing a compliant tube of physiological geometries with impedance changes, a net pressure head was induced. With Reynolds numbers ranging from 13-1350, the viscous and inertial effects of the fluid response created interesting pressure responses. The system was found to have a natural frequency near 1.69 Hz and exhibited frequency doubling. The dimensionless pressure and time responses showed a complicated pressure response that decreased in overall magnitude with increasing compression frequencies. The response is influenced by more parameters than just the compression frequency and further work is recommended to understand those parameters. Additional observations were made that suggested segmentation is not a mode of mixing. Segmentation modeled as an impedance pump can induce cyclical pressure heads that may contribute to flow in the intestine.