Numerical Modeling of Sediment Washing (Flushing) in Dams (Case Study: Sefidrood Dam)

In this research, the sediment washing operation of the Sefidrood Dam reservoir has been simulated using a Numerical Flow 3D model along with two turbulence models, RNG and LES. The results of case studies performed on the Sefidrood Dam reservoir in 2004 have been validated. To simulate, an area of ​​the reservoir with an approximate length of 700 meters and also the dam wall meshed in the form of 2 mesh blocks 1 and 2. Mesh block 1 was considered to include the dam wall, the area close to the dam wall, and the lower Gates. The dam was considered to be a solid type, which is unchangeable. Still, the geometry of the reservoir bed was defined as sediment because it changes with the movement of the flow.The results show that near the lower dischargers of the dam, the maximum amount of sediment washing up to the reservoir bed is conical. The high values ​​of the explanation coefficient (R2) and the low values ​​of the percentage of predictive error of the numerical model indicate the acceptable results of the Flow 3D model with the LES simulator in the flushing modeling of Sefidrood Dam. A comparison of the results suggests that the LES turbulence model has a better performance in estimating the maximum scour depth than the RNG turbulence model, and the results are closer to the flushing results performed in 2004.