Abstract
Augmented dispersion in the trachea during high frequency oscillation is known to be mainly due to an interaction of axial convection and lateral mixing. Visualizing experiments of intermittent oscillatory flow and sinusoidal oscillatory flow using water dynamically similar to air through a straight pipe or a pipe with circumferential grooves have been carried out and the velocity distributions during high frequency oscillation have been obtained by means of the 2 dimensional PIV flow analyzing system. The RMS radial velocity during the stationary period tends to decrease gradually in the case of intermittent oscillatory flow in a pipe with circumferential grooves. Results show that the obtained correlation coefficient between the effective diffusivity and the mean values of the RMS radial velocity during the stationary period for same conditions are very strong.
