Modeling and Predicting Scour Hole Dimensions in Siphon Spillways: A Comparative Analysis of Finite-Element Method and Metaheuristic Approaches for Optimal Prediction

Abstract

Spillways play a critical role in managing excess water discharge and controlling severe incoming floods in dams. Siphon spillways offer a practical solution for automatically draining surplus water without mechanical intervention. However, the kinetic energy of water flow and the high velocity at which water exits the spillways can lead to scouring downstream of the dam, posing stability concerns for the spillway structure. Accurate prediction of scour hole dimensions is crucial for understanding soil erosion and ensuring dam stability. Existing empirical formulas for predicting scour hole dimensions have limitations due to their narrow range of variables. Moreover, the nonlinear nature of scouring makes it challenging to develop precise simulation formulas. As a result, researchers have turned to numerical models based on the finite-element method and data-driven approaches. This study focuses on simulating the geometric dimensions of scour holes downstream of siphon spillways using a data-based model based on support vector machines (SVMs) and gene expression programming (GEP). Prediction results obtained from laboratory values and the Flow-3D numerical model were used for validation, and an optimal model was determined. By employing a data-driven approach, this research aimed to overcome the limitations of traditional formulas and provide more accurate predictions of scour hole geometry. Accurately predicting scour hole dimensions is crucial for the safety and management of dams, as it helps in designing effective countermeasures to prevent structural failures due to scour. The proposed model has potential applications in the design and management of spillways to ensure the safety and stability of dam structures.