Dynamic Pressure Fluctuations in Stepped Three-Side Spillway

Abstract

One type of outlet works in dams are Three-side spillways that despite of their hydraulic limitations and construction problems, they were being selected, in storage dams, as best option under specific topographical conditions. Considerable energy losses and great turbulence are hydraulic characteristic of these spillways. Hydraulic performance with targeting to reduce pressure fluctuations in side channel is an important issue in this type of spillways design. In this study, effect of stepping of three-side spillway’s Ogee profile on the dynamic pressure fluctuation have been investigated using finite volume method and RNG turbulence model. The turbulence intensity as a dimensionless number was used for quantitative study of dynamic pressure fluctuations. The results showed that the proposed form of ogee profile caused a significant reduction in turbulence intensity within the side channel. On the other hand, the stepped Ogee profiles of three-side spillways caused to simple construction and ease of operation.

Keywords

• Three-side spillway
• Stepped Spillway
• Dynamic pressure fluctuation
• RNG turbulent model