History effect on the turbulent viscosity in swirling pipe flow

Abstract

Turbulent swirling flow in a straight pipe is one of turbulent flows that are difficult to predict accurately by the eddy viscosity model. In this work, the Reynolds stress equation model was integrated along the fluid particle path to obtain a temporally nonlocal model. It was shown that the history effect associated with the swirling motion leads to the decrease of the eddy viscosity. The velocity profiles in a swirling pipe flow obtained from the present model agree well with experiment; the reduced eddy viscosity can account for the slow decay of the swirling motion in a pipe flow.