Mirali Mohammadi - Dept. of Civil Eng., Faculty of Eng., The University of Urmia, Urmia, Iran
DonaldW. Knight - School of Civil Engineering, Birmingham University, Edgbaton, Birmingham, England

To understand the lateral distribution of boundary shear stress, a series of measurements was undertaken for velocity and boundary shear stress in fully developed turbulent flow for a V-shaped bottom channel. The distribution results show that for the mild slope channels they are fairly flat, but that for the steep ones this is not the case. The distributions for the steep channels point to the role of secondary currents and cross sectional shape. The percentage shear force carried by the walls, %SFw, was analyzed. Previous experimental data for other channels were reassessed and were compared with the new experimental data. The results reveal that %SFw is favorably correlated with the geometry parameter, Pb/Pw. It was also found that the present channel gives low values of %SFw as the aspect ratio, B/h, increases. This result again ratifies the cross sectional shape effects..