Analysis of Flow Phenomena in Gastric Contents Induced by Human Gastric Peristalsis Using CFD |
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Authors: | Hiroyuki Kozu Isao Kobayashi Mitsutoshi Nakajima Kunihiko Uemura Seigo Sato Sosaku Ichikawa |
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Institution: | (1) Food Engineering Division, National Food Research Institute, NARO, 2-1-12 Kannondai, Tsukuba Ibaraki, 305-8642, Japan;(2) Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai, Tsukuba Ibaraki, 305-8572, Japan; |
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Abstract: | This paper uses computational fluid dynamics to simulate and analyze intragastric fluid motions induced by human peristalsis.
We created a two-dimensional computational domain of the distal stomach where peristalsis occurs. The motion of the gastric
walls induced by an antral contraction wave (ACW) on the wall of the computational domain was well simulated using a function
defined in this study. Retropulsive flow caused by ACW was observed near the occluded region, reaching its highest velocity
of approximately 12 mm/s in the narrowest region. The viscosity of the model gastric contents applied in this study hardly
affected the highest velocity, but greatly affected the velocity profile in the computational domain. The shear rate due to
gastric fluid motion was calculated using the numerical output data. The shear rate reached relatively high values of approximately
20 s−1 in the most occluded region. The shear rate profile was almost independent of the fluid viscosity. We also simulated mass
transfer of a gastric digestive enzyme (pepsin) in model gastric content when peristalsis occurs on the gastric walls. The
visualized simulation results suggest that gastric peristalsis is capable of efficiently mixing pepsin secreted from the gastric
walls with an intragastric fluid. |
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