On Flow Reversal in Turbulent Swirling Flow

Abstract

A turbulent swirling flow is studied with the aid of a variational method. The mean-flow field is expressed by the mean vorticity proportional to its curl. The total axial flux and total helicity per unit length are introduced to characterize the swirling flow, and the condition for the reversal of the axial flow near the center of flow is obtained. On this basis, the helicity injection is discussed in the light of the control of the onset of flow reversal in a turbulent swirling flow. Reference is also made to a cylindrical jet in relation to a swirling laboratory jet and an accretion-disk jet.