Abstract
Wind tunnel experiments on the turbulent characteristics of a purely oscillatory flow were performed with the aids of the Laser Doppler anemometer as well as the hot wire anemometers, along with the advanced electronic data processing system. Visualization studies by means of the smoke wire technique were also made.
The following results were obtained.
(i) Although the statistics of oscillatory flow remarkably differ from the steady turbulent flows, the elementary process which maintains the turbulence production is almost the same with that in the steady wall turbulent flows ; i. e. the bursting process, especially the ejection phase is prevailing.
(ii) Probability distributions of u' are skewed towards the positive side during the violent bursting phase.
(iii) The Reynolds stress during the ejection phase is not only stronger but also spreads higher from the wall than that of the sweep phase.
(iv) While in the acceleration period, the vertical velocity profile hardly obeys the log-law, it has the wide log-law region in the decelerating period, especially in the ejection phase.
