A numerical analysis has been performed for fully developed turbulent flow in a rectangular duct of aspect ratio 2:1, one of whose long-side walls was roughened. In calculation, an algebraic stress model was adopted in order to predict Reynolds stresses precisely. Calculated results were compared with the experimental data available. The present method can predict well a large eddy caused by anisotropic turbulence in a half-cross-section, and a small eddy is observed in the upper wall corner region. The experimental result of streamwise vorticity shows the existence of the predicted small eddy. Calculated results of normal stresses and turbulent energy are in good agreement with the experimental data. Furthermore, the evaluated terms of streamwise vorticity suggest that the turbulent stress terms of u22- u23 and u2u3 are dominant ones, being of opposite sign and much larger than the convection terms.
