Characteristics of Submerged Flow Below Gate With Sill in Non-Prismatic Channels
The characteristics of submerged flow below vertical gate with sill upstream of horizontal diverging channel reach are analyzed based on experimental investigation. The experimental program is conducted in a laboratory flume with 10 cm wide, 31 cm deep and 3.0 m long. A diverging channel reach with fixed length and constant divergence angle is used. Polygonal sills with constant height, constant upstream slope and variable downstream slope are used under the gate. These sills are tested under wide range of similar submerged flow conditions to investigate the effect of sill slope on the flow characteristics. Also, a particular sill is tested under different heights to address the effect of sill height on the flow characteristics. Both the effects of submergence and the under-gate Froude number on the flow below the gate are discussed. Different flow regimes are considered (Supercritical, critical and subcritical flow). It is found that the presence of sill under the gate upstream of diverging channel reach has a remarkable effect on the discharge coefficient of the gate. It is noticed that the submergence ratio and the upstream head ratio are not able to explain the observed variations (or scatter of data) in the discharge coefficients. These variations or scatters are completely explained by the under-gate Froude number and the differential head ratio.
Radial Hydraulic Jump
Radial hydraulic jump occurs in a stilling basin with diverging side walls. Experimental data is used to obtain the free-surface profiles and the floor-pressure profiles within the diverging basin. These profiles are used to develop generalized equations for the effective side wall forces for Froude numbers from 2 to 10. The momentum equation, which involves these forces, is then applied to develop an equation for the sequent depth ratio for the jump. For Froude numbers above 3, the sequent depth ratio is shown to be less than that for the rectangular jump. The length of the radial jump is about 70% of the length of a rectangular jump for the same initial Froude number. However, the volume of the jump is approximately the same as for the rectangular jump. The energy dissipation in the radial jump is approx 15% greater than for the rectangular jump.
Circular Hydraulic Jump
A predictive mathematical model of a circular hydraulic jump fountain display is presented. Momentum conservation, assuming a linear jump profile, is applied to obtain an equation for the sequent depth ratio for the jump. Assuming the jump length ratio is constant, the model is used to predict the relationship between jet thickness at source, jump location, and discharge. Experimental data shows that the sequent depth and energy loss for a circular jump are less and greater, respectively, than that for a rectangular jump. Results indicate the length of the circular jump is considerably less than that for the rectangular jump. In addition, the experimental findings indicate the model correctly simulates the circular hydraulic jump fountain display.