THE STUDY OF THE UPSTREAM SLOPE OF A SIPHON SPILLWAY ON ITS DISCHARGE COEFFICIENT USING FLOW3D SOFTWARE

In many projects for supplying water and energy, such as dams, the flow rate of water must be controlled to achieve this goal. To that end, a special structure, called the dam's spillway, is used to discharge the surplus water. In other words, this technique is used when the size of the dam is inadequate for storing the surplus water and avoiding the risk of flooding. Dam spillways are complex and diverse equipment, and it is very important for designers to understand the hydraulic behavior of this equipment and to be able to analyze specific physical parameters by changing the angle of the slope above the siphon spillway in the KWPTI (Khuzestan water and power authority) laboratory. In this research, the governing equations were solved by the finite volume discrimination method (flow 3D software), and the standard K-£ model was used to estimate the turbulent flow. A structured grid was used to fit the irregular boundaries, and the volume of fluid (VOF) method was used to solve the complex free-surface problem. The free surface, velocities, and pressures on the siphon spillway were obtained by the numerical simulation of the turbulence. The results of the numerical method were in good agreement with the experimental results that were obtained. The results of the tests that were conducted in this research indicated the discharge coefficient decreased as the angle of the slope increased.