Univrsity Of Tehran Press Water and Irrigation Management 2251-6298 15 3 2025 11 22 Investigating Effect of Flow Contraction on Discharge Coefficient of Lopac Gates Using Support Vector Machines Investigating Effect of Flow Contraction on Discharge Coefficient of Lopac Gates Using Support Vector Machines 497 508 103130 10.22059/jwim.2025.392612.1217 FA Kazem Shahverdi Department of Water Science and Engineering, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran. Sharareh Yari Department of Water Science and Engineering, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran. Journal Article 2025 04 13 One of the main important and influential factors on the performance of water conveyance and distribution systems is the type of structure and its performance. The LOPAC gate is one of these structures, whose discharge coefficient is a key factor in estimating the flow rate. In this research, after dimensional analysis and identifying the effective parameters, including the opening angle, submergence ratio (the ratio of downstream depth to upstream depth), and opening ratio (the ratio of LOPAC gate opening to canal width), the discharge coefficient of a LOPAC gate under semi opened submerged operating conditions with and without contraction was predicted using a support vector machine (SVM). To this end, a support vector machine-based prediction model was developed using experimental and numerical data to estimate the discharge coefficient of a Sluice gate under submerged flow conditions. Thus, 70% of the data was used for training and 30% for testing. After optimizing the support vector machine parameters using systematic methods, different models with varying input parameter combinations were evaluated. The results showed that the optimal model using the submergence ratio and opening ratio as the main input factors provided the highest accuracy with a correlation coefficient of 0.984 and a root mean square error of 0.006. One of the main important and influential factors on the performance of water conveyance and distribution systems is the type of structure and its performance. The LOPAC gate is one of these structures, whose discharge coefficient is a key factor in estimating the flow rate. In this research, after dimensional analysis and identifying the effective parameters, including the opening angle, submergence ratio (the ratio of downstream depth to upstream depth), and opening ratio (the ratio of LOPAC gate opening to canal width), the discharge coefficient of a LOPAC gate under semi opened submerged operating conditions with and without contraction was predicted using a support vector machine (SVM). To this end, a support vector machine-based prediction model was developed using experimental and numerical data to estimate the discharge coefficient of a Sluice gate under submerged flow conditions. Thus, 70% of the data was used for training and 30% for testing. After optimizing the support vector machine parameters using systematic methods, different models with varying input parameter combinations were evaluated. The results showed that the optimal model using the submergence ratio and opening ratio as the main input factors provided the highest accuracy with a correlation coefficient of 0.984 and a root mean square error of 0.006. https://jwim.ut.ac.ir/article_103130_44767a22af2f93f2b03ae2cb14791a6b.pdf