Effects of Bucket Type and Angle on Downstream Nappe Wind Caused by a Turbulent Jet

Abstract

The downstream nappe wind caused by flood discharge has a great influence on the rainfall distribution, the operational safety of dams, and their surrounding ecological environments. A physical experiment was conducted to measure the spatial distribution of the downstream nappe wind and the splash for a continuous bucket (CB) and a tongue-shaped bucket (TB) for five bucket angles (40°, 45°, 50°, 55°, and 60°). The experimental results demonstrate that the trajectory width and height of the nappe increase as the angles increase, but the effect on the length is converse. The wind velocity and splash weight of the two buckets decrease along the flowing direction. In the lateral direction, the wind velocity and splash weight for the CB decrease as y increases, but the wind velocity of the TB trends to humplike; its splash weight decreases near the axis of the bucket, and is stable in the other region. In the vertical direction, the velocity for the CB increases and then decreases as z increases, but that for the TB decreases monotonously. The velocity of the wind and weight of the splash for the CB decreases with the increasing angles, but those of the TB peak at 45°. The findings are useful for the more accurate prediction of rainfall.

Three-Dimensional Flow of a Vortex Drop Shaft Spillway with an Elliptical Tangential Inlet

“…Vortex drop shaft (VDS) spillways are widely used discharge structures in China owing to various excellent performances, such as high-energy dissipation, steady flow regime and good terrain adaptability [1]. Additionally, compared with traditional ski-jump energy dissipaters, VDS spillways can transfer the flood discharge and energy dissipation task into the tunnel, which effectively avoids outlet atomization formed by the interaction between air boundary water and reduces the impact on the ecological environment [2,3]. Examples of existing VDS spillway include Shapai, China [4], Xiaowan, China [5], Jiayan, China [6], etc.…”

An Experimental Study on the Effects of Atomized Rain of a High Velocity Waterjet to Downstream Area in Low Ambient Pressure Environment

“…Liu et al [17] measured rain intensity distribution splashed by high-velocity waterjets with velocities of 37.08 m/s, 52.40 m/s and 58.59 m/s. Liu et al [15], Liu et al [18], and Lian et al [19,20] carried out diverse random splash experiments induced by a single waterjet with relatively low velocities. In such experiments, the distribution law of point average rain intensity is used to explore the formation of the random splash source and the influence mechanism of the atomized rain field, which is introduced in the application of the parameter calibration for numerical models to predict the full-scale distribution of atomized rain in prototype engineering [14][15][16]; the distribution law of surface average rain amount is designed to explore the relationship between inflow hydraulic conditions and localized atomized rain, which has been qualitatively extended to analyze the impact and protection design in local area [10].…”

“…In such experiments, the distribution law of point average rain intensity is used to explore the formation of the random splash source and the influence mechanism of the atomized rain field, which is introduced in the application of the parameter calibration for numerical models to predict the full-scale distribution of atomized rain in prototype engineering [14][15][16]; the distribution law of surface average rain amount is designed to explore the relationship between inflow hydraulic conditions and localized atomized rain, which has been qualitatively extended to analyze the impact and protection design in local area [10]. The random splash process can be divided into three steps [15,[18][19][20]. First, when the aerated waterjet comes into contact with the water cushion, a great impact force is produced, similar to solid crashes.…”