Numerical Investigation of Air Detrainment Process in Chute Flows

One of the most important factors in designing spillways is to consider sufficient discharge capacity. Possible creation of negative pressure over spillway during high flood conditions can be a potential for occurrence of cavitation damage. Flow aeration might be one of the best ways to prevent this phenomenon. Realizing the air detrainment process along the chutes is a key problem in designing aerators. Although experiments on hydraulic models have their own advantages, but these methods are expensive and time consuming. In this study the CFD code FLOW-3D® has been used to determine the spillway flow air concentration in case of aeration by means of deflectors. Comparison of obtained results with the Kramer's experimental results shows good agreement. It has been realized that the flow bottom air concentration downstream of deflectors reduces exponentially.