TRANSITION TO TURBULENCE IN A PULSATILE PIPE FLOW - 1. WAVE FORMS AND DISTRIBUTION OF PULSATILE VELOCITIES NEAR TRANSITION REGION.

Abstract

Pulsatile flow in a circular pipe can be characterized by three parameters, i. e. , the dimensionless frequency, the time-averaged Reynolds number, and the velocity amplitude ratio. Here by changing the time-averaged Reynolds number from 0 to about 1. 4x10**4, velocity measurements were made by means of a hot wire anemometer. From output signals of pulsatile velocity the flows near the transition region were classified into the following three types; (1) laminar flow, (2) disturbed flow, and (3) turbulent flow. The distributions of oscillatory and time-averaged axial velocity components in each type of flow were characterized with respect to time-averaged Reynolds number.