Laboratory Investigations on Development of Energy Dissipators for Square Shaped Outlets

The paper examines the effectiveness of prevalent USBR type VI models and proposes new shorter and efficient designs by means of laboratory experimentation. The models are tested on 4cm x 4cm square opening (d = 4cm) with an erodible material and a constant run time for inflow Froude no Fr = 6.83 with a diverging side walls at a slope of 1 V:0.75 H up to a length of 3.5d. A non-dimensional number called as performance number has been used as for comparison of performance of the models. Several appurtenances various shapes and sizes like splitter block, impact wall, intermediate sill, and end sills are tested in the laboratory. It has been found that this special pentagonal shaped block quite is helpful in spreading the jet of water in a shorter length, resulting into better and more energy dissipation. It was found that the length of energy dissipator models can be reduced by more than 15% as compared to USBR impact type VI energy dissipator model without sacrificing the performance.