Abstract: The intake vortices of pressure inlets have destructive effect on hydraulic machinery and buildings. It is of practical significance to discuss the generation mechanism of vortex, especially of intake vortex, to reveal the law of movement, and to seek effective measures to control the damage of vortex. Studies on the inlet vortices properties and influencing factors mainly focused on single-channel and single inlet water rather than vortex properties of double inlets or multiple inlets. Submerged outflow of dual-pressure inlet is adopted to observe water flow field and vortex properties by changing the shape and arrangement of the inlet under different submergence depths. Results show that the duration time, frequency and intensity of intake vortex decrease with the increasing of relative submergence depth. In different submerged water depths, the diameter and intensity of vertical vortex show a process of increasing first and then decreasing as the submergence depth increases. Increasing the distance between the inlets appropriately could change the vortex type and reduce the duration and frequency of the intake vortex.

Key words: dual-pressure inlet, arrangement of inlet, intake vortex, flow pattern, flow velocity