Q. Energy dissipation at outlets - typical drainage outlet?

Flow velocity at outlets is generally high. Without proper control of this energy, subsequent bank erosion can result in failure of the banks. Consequently some energy dissipating structures are designed to cope with this problem. Impact energy dissipaters can be provided atoutlets by making use of impact walls to dissipate energy. Otherwise the flows at outlet are dispersed artificially to achieve a substantial loss of energy. Though problem of cavitation may take place in this kind of energy dissipating structures.

Fig: A typical drainage outlet