FLOW VISUALIZATION IN PULMONARY ARTERY MODELS.

The photographs taken showed only two-dimensional fluid flow behavior, but by physically observing the flow fields through the glass models, a three-dimensional sketch could be described. For example, in the secondary flow regions, it was observed that the particles seemed to travel down the wall in the pattern of a helix, which was probably caused by the particles hitting the wall and traveling towards the jet and then being pushed back towards the wall by the jet. In the right arm, the particles traveled down the branch in a counterclockwise direction while in the left branch, the particles traveled down the branch in a clockwise direction. It was also observed that the directions of these secondary flows were not a function of the location where the jet impinged on the distal left branch wall. The helical patterns or secondary flow could be distinguished in a few photographs.