Evaluation of Submergence Limit and Head Loss in Flow Measuring Flumes Using Flow-3D Predictive Modeling

Conducting physical experiments to measure submergence ratio, limit, and head loss in flume flows can be resource-intensive and time-consuming. Consequently, there is a growing need to develop modeling techniques for such measurements. The goal of this study was to calibrate and employ the computational fluid dynamics (CFD) platform FLOW-3D^® code to implement varying downstream bottom elevation in a studied rectangular flume that enables measurement of submergence ratio, limit, and head loss under three flow rates (0.112, 0.169, and 0.320 \({m}^{3}\)/s) for the studied flume. Flow rates of 0.112, 0.169, and 0.320 m³/s were examined across three flows: Flow 1, Flow 2, and Flow 3. Calibration of FLOW-3D^® code was achieved by comparing its results with published experimental data (R² > 0.98 and RMSE < 1.5 cm). Variations in downstream bottom elevations were analyzed to determine the submergence limit, resulting in values of 0.21, 0.24, and 0.25 for Flow 1, Flow 2, and Flow 3, respectively. Additionally, the study observed a maximum head loss of 32.5% when the submergence ratio exceeded its limit in Flow 1.