A multiphasic, fluid-structure interaction-based model of peristalsis in the Upper Gastrointestinal tract*

In previous gastrointestinal (GI) models developed by our group, we’ve studied the phenomena of bolus transport in the esophagus and peristalsis in the stomach. The two organs were modeled in isolation and the gastric contents were limited to a single phase. The development of a new multiphase solver by our group for the open-source FSI framework IBAMR has enabled us to now model the gastric contents as a multiphase mixture. The goal of this work is to study the effects of gastric peristalsis on the gas-liquid contents in the entire Upper GI tract. The combined model allows for transfer of fluid between the stomach and esophagus. This enables the model to simulate 'acid reflux' which affects a large percentage of the adult population. With the help of this model, we aim to study the volume of acid reflux and its composition as a function of stomach contents and intensity of gastric peristalsis. A detailed numerical model that simulates acid reflux will also help us understand how the geometry at the Esophagogastric Junction (EGJ) affects the mechanism of reflux. This knowledge can assist in developing new medical techniques for treating GERD (Gastroesophageal Reflux Disease).