Direct numerical simulation of turbulent flows in curved and helically coiled pipes

Fully developed, statistically steady turbulent flow in straight, curved an d helically coiled pipes is studied by means of direct numerical simulation to show the influence of curvature and torsion on turbulent flow. The inco mpressible Navier-Stokes equations, expressed in an orthogonal helical coor dinate system, are integrated numerically by using second order central sch emes in space and time. Besides the mean flow quantities and the rms values , vector plots and the stream function are shown to give an impression of t he induced mean secondary flow. (C) 2001 Elsevier Science Ltd. All rights r eserved.