Abstract
The turbulent Poiscuille or Couette-Poiscuille flows inside a square or rectangular cross-sectional duct are of considerable engineering interest because of their relevance to compact heat exchangers and gas-turbine cooling systems. By computing the heated turbulent flow through a square duct with one ridged wall, new secondary flows were revealed near the ridges. The relationship between the secondary flow structure and the moving wall is not addressed. The virtex structure is clearly visible, where solid and dashed lines represent counter-clockwise and clockwise rotation, respectively. The turbulence level near the moving wall is reduced compared to other bounding walls, which are caused by the insufficient mean shear rates. The anisotropy invariant analysis indicates that along the wall bisector at the top half of the duct, turbulence structure gradually moves toward a rod-like axisymmetric state as the moving-wall velocity is increased. The anisotropy states near the bottom stationary wall resemble those presented in turbulent channel flow or boundary layers. © 2007 Copyright © 2007 Elsevier B.V. All rights reserved..