The structure of turbulence in pulsatile pipe flows

Abstract

This paper describes the fundamental feature of pulsatile transitional and fully turbulent pipe flows. First, the effect of pulsation on the behavior of turbulent slugs in the developing region of circular pipe is clarified. Second, the distributions of turbulence intensity and Reynolds shear stress in fully turbulent pulsatile pipe flow are compared with their respective distributions in fully turbulent steady pipe flow. Generation region of turbulence and radial propagation time of the turbulence are determined from these distributions. Finally the turbulence structure in pulsatile pipe flows with and without relaminarization, i. e., reverse transition, is made clear by means of the conditional sampling method based on the four quadrant classification.