Row and bed deviation angle in curved open channels

In a curved channel of limited width, such as a curved channel sediment excluder, the primary velocity distribution is affected by the presence of the spiral motion and by the effect of the restricted width/depth ratio. A modified logarithmic law to describe the distribution of the primary velocity on the vertical is suggested and this accommodates the case when the maximum primary velocity is located below the water surface. Using this law and assuming non-linear distribution of the primary turbulent shear stress, the distribution of the radial velocity in the vertical is derived which takes into consideration the effect of the width-depth ratio. An expression for the deviation angle of the flow at the bed, reflecting the effects of the bed roughness as well as the width-depth ratio is also given. The result of the analysis is that the radial velocity distribution as well as the bed deviation angle are significantly affected by the width-depth ratio in addition to the bed roughness. Predicted and observed values compare well. The investigation is confined to variation of velocities and shear stresses in a vertical, and not laterally.