Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.
Turbulent secondary flows are motions in the transverse
plane, perpendicular to a main, axial flow. They are
encountered in non-circular ducts and, although the velocity is
only of the order of 1-3% of the streamwise bulk velocity, can
still affect the characteristics of the mean flow and the turbulent
structure. In this work the focus is on secondary flow in semicircular
ducts. Both numerical and experimental analyses are
reported. It is found that the secondary flow in semi-circular
ducts consists of two pairs of counter rotating corner vortices,
with a velocity in the range reported previously for related
configurations. Agreement between simulation and
experimental results are good when using a second moment
closure turbulence model.