Effects of Cutoff Wall Shape and Size of Dam Gates on Vortex Formation Upstream of Dams

The formation of vortices behind the gates of diversion dams is an operational challenge. Such vortices lead to vibration and corrosion in the gate, reducing the lifetime and raising the operational cost of the dam. This study investigated these vortices and their formation. It was found that the gate or cutoff wall was not the only explanation for the vortices; the closed side gates also contribute to vortex formation. Furthermore, an increase in the gate width reduced vorticity; the vortex size experienced a 200% reduction as the gate size increased by 200%. The cutoff wall diameter was another determinant. An increase in the cutoff wall diameter raised vorticity. The vortices increased by 50% as the wall diameter increased by 150%.