ANERGY DISSIPATION ARRANGEMENTS FOR SPILLWAYS AND THEIR PROTOTYPE BEHAVIOUR

Abstract

In this dissertation an attempt has been made to study the design requirements and actual behaviour of the various energy dissipation devices adopted downstream of the spillways of medium and high dams in India, and to analyse, the data so collected, dimensionally to evaluate the various design parameters to evolve charts and relations to serve as a ready guidance for future designs. The study is divided into 6 chapters, the first chapter dealing with the scope of the present studies and the objective thereof: The second chapter is devoted to the various forms of hydraulic jump, its practical considerations and the design criteria of energy dissipation. In the third chapter is dealt the dimensional analysis for the specific case of Ski-Jump type of bucket type energy dissipator. The fourth chapter deals with the various design considerations for the design of different types of energy dissipators, and the discussions on the several aspects of design by the various other authorities. Also are included tables containing the hydraulic details and details of compo-nent parts of various types of dissipating devices adopted at Indian dams. From a Dimensional and Statistical analysis of the various Ski-Jump buckets adopted and proposed to be adopted in India, graphs have been drawn and equations worked 2. out to serve as guide for the fixation of the radius of bucket and the exit angle, before finally proceeding with its testing on models. This would obviously avoid many trials in the model testing and thus ssre time. The analysis of this type has not been done for stilling basins inview of meagre data available. The chapter No. 5 deals with the prototype behavi-our of energy dissipating devices adopted on various Indian dams. The prototype behaviour of Interacting Jet dissipator adopted at Koilsagar project in Andhra Pradesh has been dealt in detail being unique and the first of its type, and which has functioned satisfactorily, The conclusions are outl~nad in chapter number 6, which lays down the suggested design practice for the various energy dissipator devices, and also the formulae evolved as a result of dimensional and statisticcl. analysis. The model testing is no doubt a final resort before adopting any type or otherwise of energy dissipating deice on any structure of considerable importance.