Efficient design optimization and investigation by combining numerical and physical models

Experiments of the spilling structures of a large dam have been conducted at the Institute of Hydraulic Engineering of the University of Innsbruck. These experiments have been accompanied by numerical studies to compare numerical with experimental results and to explore the potential of hybrid models for future investigations. Because of the complex geometry the 3D flow field had to be resolved and therefore the commercial software Flow-3D has been used. A quantitative comparison was performed using the results from capacity and pressure measurements. Additional information was gained by qualitatively comparing the flow phenomena leading to possible problems during operation of the spillway. The comparison was very good with respect to quantitative and to qualitative criteria. Due to the detailed information from numerical tests the coarse grid information resulting from the experiments could be refined. Similar future investigations can be performed using a hybrid approach by combining numerical and experimental investigations. This will lead to cost and time savings without loss of quality. The comparison has also shown that a major disadvantage of pure numerical investigations is the fact that problems must be foreseen right from the start. Otherwise corresponding computational runs are not performed and difficulties are not recognized.