Abstract:
Free surface vortices at hydropower intakes can significantly reduce turbine efficiency
and cause premature mechanical failure; in siphon spillways the vorticity and the air entrainment to
the pressure circuit can reduce the spillway discharge capacity. Therefore preventing the occurrence
of vortices is very important in the design of water intakes. Due to the complexity of the
phenomena, physical models are a valuable help and, apart from the scale effects, vortices
observations on physical models can give valuable results that aid in the design of hydraulic
structures where vortices might appear.
In this paper, the formation of free surface vortices in two types of submerged hydraulic structures
and several solutions to prevent vortices formation are presented. The experimental studies were
performed in two scaled physical models which allowed testing several solutions for anti-vortex
devices that proved to be generally efficient and can be easily incorporated in the final geometry of
water intakes.
