Study on Hydraulic Characteristic of Submerged Jet with Depression Angle Dived into Plunge Pool from the Underwater Surface

Abstract

Experiment research on submerged jet with depression angle dived into plunge pool from near-surface was carried out. The results showed that this type of energy dissipation type has good effect in improving the energy dissipation rate, reducing the surface fluctuation and reducing near-bed velocity and so on. Calculation formulas of conjugate depth and energy dissipation were obtained through theory analysis of submerged hydraulic jump in water cushion. Formula analysis showed that for high Froude number flow at a certain downstream depth, to obtain stable submerge hydraulic jump through adjusting size of jet exit, by decreasing its width is better way than by increasing height. When flow Froude number is larger sudden expansion ratio is more sensitive to energy dissipation, therefor to improving effect of energy dissipation by decreasing jet exit’s width or increasing plunge pool’s width can be used.