Author(s): Yoiuchi Yasuda; Iwao Ohtsu; Masayuki Takahashi
Linked Author(s): Masayuki Takahashi, Iwao Ohtsu
Keywords: Erated supercritical flow; Energy dissipator; Hydraulic jump. Figure 1. -Jump formation with a surface roller in a steep sloping channel (55 degrees)
Abstract: The flow condition of plunging flows in steep sloping channels depends on the inflow condition, the downstream depth, and the angle of slope. In the case of the prototype, aerated supercritical flow is formed on the spillway. Many researchers have investigated the transition from supercritical to subcritical flow in sloping channels by using a physical model. But the effect of aerated inflow on flow characteristics of the plunging flow has not been made clear. For the hydraulic design of stilling basin in sloping channels, it is significant to clarify the effect of aerated inflow on the flow condition of the plunging flow. This paper presents the effect of aerated inflow on characteristics of the plunging flow in steep sloping channels (30 and 55 degrees) with a horizontal channel portion. The experimental investigation reveals that the flow condition and a reverse flow length are affected by the air-concentration ratio of the aerated inflow. The flow condition has been classified. The maximum velocity decay and the velocity vector in the plunging flow support the effect of the buoyancy due to air-bubble. The relation between the toe location and the downstream depth of the plunging flow has been derived from the momentum equation considering the air-concentration ratio in the transition flow.
Year: 2007