Impact of reduced gravity on food mixing and emptying in human stomach: A numerical simulation study.

This article focuses on a computational fluid dynamics (CFD) study investigating how reduced gravity conditions affect gastric mixing and emptying in the human stomach. Using a 3D stomach model and simulations based on the open-source OpenFOAM toolbox, the study compares digestion processes under zero gravity (0G), half gravity (0.5G), and Earth gravity (1G). Results indicate that gravity facilitates the settling and emptying of food toward the pylorus, with food retention delayed by about six minutes under zero gravity when initially located in the proximal stomach. Terminal antral contractions (TACs) enhance emptying and mixing primarily in the distal stomach, with their effects amplified under normal gravity. The study also finds that gravity influences the intragastric distribution of food and pH, affecting digestive dynamics, and highlights the need for further model refinement to incorporate realistic gastric content rheology and pyloric dynamics for more accurate predictions.