Comparative Evaluation of Soft Computing Models for Predicting the Discharge Coefficient of Arced Labyrinth Weirs

نوع مقاله : مقاله پژوهشی

نویسندگان

Department of Civil Engineering, Na.C., Islamic Azad University, Najafabad, Iran.

10.22034/nawee.2026.585562.1232
چکیده
Objective: The accurate prediction of the discharge coefficient (e hydraulic design of labyrinth weirs. While existing literature extensively covers conventional vertical-sidewall geometries, there is a critical knowledge gap regarding the synergistic effect of sloped sidewalls and arced planform geometry on discharge capacity. This study addresses this limitation by investigating and predicting Cd​ for arced labyrinth weirs with varying sidewall slopes.
Methods: Using a comprehensive dataset of 277 experimental runs from a laboratory flume, five dimensionless parameters—namely sional analysis to capture both geometric and hydraulic complexity- were used as inputs for three soft computing approaches: Support Vector Machine (SVM), Gene Expression Programming (GEP), and Artificial Neural Network (ANN).
Results: All three data‑driven approaches produced satisfactory predictions of Cd. However, the ANN model based on a multilayer perceptron (MLP) demonstrated the best performance. The optimal architecture was MLP 5‑9‑1 trained using the BFGS algorithm, with the SOS error function, a logistic activation function in the hidden layer, and an identity activation function in the output layer. During training and validation, the performance metrics (RMSE, MAE, R², Cd(DDR(max))) were (0.022, 0.0145, 0.8402, 11.436) and (0.0199, 0.0145, 0.8961, 12.805), respectively. Graphical analyses also showed strong agreement between observed and predicted Cd values across different dataset quartiles.
Conclusions: The findings confirm that the MLP framework provides a robust and reliable alternative for hydraulic engineers, filling the current modeling void for non-conventional labyrinth weirs. This approach offers a practical tool for spillway optimization where complex geometric interactions preclude the use of simplified linear regressions.

کلیدواژه‌ها