Accurate stage-discharge rating curves of hydraulic controls are fundamental for operating and maintaining
hydraulic structures. In many cases such as gate-controlled service spillways, the relationship between reservoir
elevation and discharge becomes complicated, and standardized rating curves may not be suitable. A physical model
or 3D CFD simulation can be used to develop site-specific rating curves to analyze all potential combinations of gate
openings and reservoir elevations.
Using data from a recent USBR project, the current study demonstrates the use of 3D CFD to automatically generate a spillway rating curve of a radial-gated chute-type spillway. We will first present methods to identify optimal model setup approaches (e.g., meshing configurations and numerical methods) to minimize compute time and maximize the accuracy of the model-predicted discharge. The second step will be to use workflow automation tools to generate a full rating curve under the range of expected reservoir elevations and gate heights. Comparisons between CFD and physical modeling approaches will be provided to evaluate differences in accuracy, time, and cost.