Sudden-Enlargement Energy Dissipater for Mica Dam

The design of a sudden-enlargement energy dissipator to reduce the operating heads and, hence, the velocities along the flow surfaces in the Mica Dam low-level outlets is developed with the aid of hydraulic models using a cavitation member as a criterion of similarity. The influence of the number, size, arrangement, and shape of the flow passages entering a sudden enlargement on the cavitation potential and performance of the dissipator is evaluated. The cavitation numbers for cavitation for various designs are listed and the number for incipient cavitation damage is given for the Mica Dam design. The ability of concrete surfaces to withstand rapidly fluctuating pressures of large magnitude is indicated.