Fig. 4.

Schematic of the setup of the esophageal transport model. Left: the elastic esophagus, a cylindrical tube is immersed in a background fluid box. The esophageal top is fixed. The upper esophagus is initially filled with a bolus and the lower part is filled with a thin liquid layer in the lumen. The top surface of the rectangular computational domain has zero-velocity boundary conditions. All the other five surfaces have traction-free boundary conditions. Right: a cross-sectional cut of the esophageal wall showing three layers. The three layers, from the inside to the outside, are mucosa, circular muscle, and longitudinal muscle.