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.
Hydraulic Jump within Gradually Expanding Channel
This expanding channel jump is considered to behave as a section of a circular jump. Equations describing the characteristics of the expanding channel jump are derived. The observations were conducted using six different angles of divergence. The experimental results showed a close agreement with the theoretical solutions. The general equation developed for the jump, with proper evaluation of the side pressure force effect, describes the phenomenon regardless of the angle of divergence. An empirical expression for approximating the location of the jump within the transition was also developed.
CIRCULAR HYDRAULIC JUMP
Hydraulic jumps involving radial flow, as in diverging stilling basins, have not been properly analyzed. Dynamical considerations disclose that the radial flow jump involves a force not found in the rectangular jump. As a consequence, the sequent depth and energy loss for a radial jump are less and greater respectively than that for a rectangular jump. In addition, experimental findings indicate that the length of the radial jump is less than that of the rectangular jump.