Fig 3. Frames from model simulations of AP with partial occlusion, for open and closed trachea.

Each frame shows half the symmetric tubule. A. Closed trachea. Lumen pressure is spatially uniform and increases as soon as AP begins. B. Open trachea. Lumen pressure is negligible until occlusion is almost complete. Pressure is uniform everywhere in the lumen except at stenosis, where flow is fastest. Maximal occlusion shown ~ 90%. C. Detail of open-trachea AP. Maximal occlusion precedes maximal pressure. Pressure distal to pinch forces fluid leakage and reduces occlusion as wave moves distally. Identical parameters (stiffness, viscosity, force input). Frames every 1.0 sec (A, B) and 0.5 sec (C).