The flow around the first branch of the human bronchial airway was investigated through experiments and numerical simulations. The target flow was an oscillatory flow simulating resting human respiration. In the experiment, velocity distributions were measured using PIV and PTV with a resin model. The numerical simulation was conducted under the same conditions as the experiment, using three-dimensional unsteady calculations to obtain velocity and pressure distributions. PIV measurements revealed that during inhalation, relatively low velocity regions appear near the wall.. Both numerical simulation and PTV measurement indicated the presence of flow reversal near the wall that is not synchronized with the breathing cycle. The pressure distribution obtained from the numerical simulation showed that this region has a lower pressure than the other regions.
YAMADA et al. (Wed,) studied this question.