Abstract: The measures to eliminate vortexes in the intakes of hydraulic structures such as power station, diversion tunnel, inverted siphon culvert, and inverted siphon river course were studied through a series of model test, in which the inducement factors of the vortex formation in practical projects were considered and the experimental process of vortex elimination was analyzed in detail. The inducements of the vortex formation at the vertical shaft in front of the intakes are very complicated. To eliminate the vertical shaft eddies induced by plane backflow, unsymmetrical inflow, and lateral inflow , we can set floating embankment to avoid backflow (e.g., in diversion tunnel) or heighten the wing walls to block the lateral flow (e.g., in inverted siphon river course). For the intakes with good flow condition, vertical shaft eddies may also be generated due to the inlet shape. This kind of vortexes could be eliminated by moving the tangency point of the elliptic curve at intake top up to the highest operation water level or adjusting the vertical core walls to be inclined upstream, by which the vortex area may be compressed and the flow can be guided to discharge unhindered and smoothly.

Key words:  hydraulics ,    vortex  ,  intakes  ,   model test  ,   measures of vortexes eliminating