Hydraulic performance characteristics of a vortical spillway with a tangential vortex generator in the flow

Conclusions

Model investigations of the hydraulic operating conditions of a vortical tunnel spillway with a tangential vortex generator indicated that:

a trend toward leveling of the core axis is observed with increasing geometric parameter A of the vortex generator both with and without air fed into the conduit;

insignificant underflooding of the outlet section of the tunnel (their difference for all regimes does not exceed 1.7%) exerts a minor influence on the carrying capacity of the spillway; here, underflooding even increases the flow rate of the spillway in the absence of air when A=0.925 and 1.245;

an air feed also has little effect on the carrying capacity of the structure, with the exception of the layout containing a vortex generator with A=0.6 (Δ=6.04% when A=0.6, Δ=0% when A=0.925, and an air feed increases the flow rate of the spillway by Δ=1.86% when A=1.245);

significant vacuums, the absolute values of which drop rapidly from H_co=−2.7 m to H_co=−1 m with increasing A, are observed for regimes with no air fed to the core;

air fed into the core sharply lowers the vacuum in the latter, and its value approaches zero;

the center of the core at the end of the vortex generator shifts toward the axis of the conduit with increasing parameter A; and,

regimes with no air fed to the core are most favorable in terms of pressure distribution on the wall of the conduit.