TOPIC HIGHLIGHT

The morphology of tissue structures composing the pyloric orifice is thought to play a role in effectively mixing aqueous gastric effl uent 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 i so la te and compare geometr i c and k inemat i c 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 outfl ow and luminal constriction is likely to enhance homogenization of gastric effluent with duodenal secretions