Challenges with air demand for the refurbishment of bottom outlets

In Sweden, many bottom outlets which were used to bypass river floods during dam construction were sealed after completion of the dams. Dam safety regulations today lead to the need to re-commission them to release water at normal reservoir levels. The resulting air demand becomes an issue of concern for their safe operation. Using field measurements and CFD modelling, the air-water flow behaviour of the outlets at Moforsen dam have been studied, providing a basis for recommisioning them, and for potential structural modifications.