Experimental Investigation of Screen as Energy Dissipators in the Movable-Bed Channel

The experimental results indicate that screens with a certain porosity placed vertically in the supercritical flow direction could dissipate a considerable amount of flow energy. Unlike the former studies which have been carried out in the fixed-bed flumes, this study investigates the energy dissipation through the screen in the movable bed at the downstream of the screen. The experiments have been carried out by the screens with 40% and 50% porosities, single and double arrangements of screens and three different bed particle sizes. The supercritical Froude number varied in the range of 5-18. According to the results, double screens with 40% porosity have the highest energy dissipation. Also, the single screens with 50% porosity have the minimum bed scour for a constant amount of energy dissipation. The theoretical multivariate equations were derived based on dimensional analysis, and the related coefficients were obtained by using experimental results.