Evaluation of Hydraulic Jump on Dentate Blocks Stilling Basin

The generated kinetic energy at the toe of spillways should be dissipated in the shortest basin to provide normal condition downstream of the river. This research aims to introduce the roughened stilling basin by means of roughness elements (dentate blocks) with new geometry form and arrangement. The study also investigates the effect of different parameters of hydraulic jump on this new stilling basin for the Froude numbers in the range of 11 to 14. The experimental results show a reduction of hydraulic jump parameters on dentate blocks stilling basin while compared to the smooth bed. Length of hydraulic jump and sequent depth was reduced by about 50-60% and 10-12%، respectively. Finally the required roughness length and length of hydraulic jump on dentate blocks stilling basin were compared with the smooth bed basin. For dentate block length of basin was 50-60 percent less and the length of hydraulic jump was only 35-40 percent less than the smooth basin.