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World J Gastroenterol. Mar 7, 2007; 13(9): 1365-1371
Published online Mar 7, 2007. doi: 10.3748/wjg.v13.i9.1365
Mechanics of flow and mixing at antroduodenal junction
Seth Dillard, Sreedevi Krishnan, HS Udaykumar
Seth Dillard, Sreedevi Krishnan, HS Udaykumar, Department of Mechanical Engineering, University of Iowa, United States
Author contributions: All authors contributed equally to the work.
Correspondence to: HS Udaykumar, Associate Professor, Mechanical Engineering, University of Iowa, 2408 Seamans Center, Iowa City, IA 52242, United States. ush@engineering.uiowa.edu
Telephone: +1-319-3840832 Fax: +1-319-3355669
Received: December 9, 2006
Revised: January 18, 2007
Accepted: February 8, 2007
Published online: March 7, 2007
Abstract

The morphology of tissue structures composing the pyloric orifice is thought to play a role in effectively mixing aqueous gastric effluent with duodenal secretions. To understand the physical mechanisms leading to efficient digestion requires computational models that allow for analyses of the contributions of individual structural components. Thus, we have simulated 2-D channel flows through representative models of the duodenum with moving boundary capabilities in order to quantitatively assess the importance of notable features. A well-tested flow solver was used to computationally isolate and compare geometric and kinematic parameters that lead to various characteristics of fluid motion at the antroduodenal junction. Scalar variance measurement was incorporated to quantify the mixing effectiveness of each component. It was found that the asymmetric geometry of the pyloric orifice in concert with intermittent gastric outflow and luminal constriction is likely to enhance homogenization of gastric effluent with duodenal secretions.

Keywords: Computational fluid dynamics, Mixing, Homogenization