عنوان مقاله [English]
One of the most common ways to reduce kinetic energy dissipation is to use a stilling basin. One of the most important parameters of the stilling basin, which has a great impact on its construction costs, is the length of the basin, so it is possible to reduce construction costs by examining and studying it carefully. In this study, the stilling basin was first performed and calibrated using the laboratory data of Chanson and Chachru. Then the spillway of the Chaili dam was investigated using Flow-3D software with RNG turbulence modeling model and flow hydraulic parameters by applying changes along the stilling basin. Studies show that increasing and decreasing the length of the stilling basin and the placement of the end-sill have different effects on the flow characteristics as well as the amount of energy loss. Since increasing the amount of energy consumption is desirable, so among the various modes of the length of the stilling basin, increasing the length of the basin is selected. Increasing the length of the stilling basin increases the energy dissipation and reduces the pressure and force on the end-sill. So that the energy dissipation by increasing the length of the stilling basin to 90 meters and 120 meters compared to the reference model with a length of 75 meters increased by 0.55 and 2.8 percent, respectively, and the force applied to the vertical wall of the end sill, respectively, 5.63 and 3.45 percent decreased. The effect of the placement of the rectangular block on the force and the amount of energy dissipation of the flow was evaluated. The results showed that creating a rectangular block inside the stilling basin reduced the secondary depth of jump and reduced the strength by 7.1% and increased the relative energy loss by 14.31% compared to the stilling basin in the flat state so that the use of blocks They will make the stilling basin than the changes along the stilling basin. Based on this, the results of this research and the methods used in it can be used as an idea to determine the optimal stilling basin.