Effect of Jet Angle Variation on Hydraulic Properties of Rectangular Dissipative Wells
When the narrow topographic conditions at the outlet of the discharge building make it difficult to adapt to the lengthwise arrangement of conventional underflow energy dissipators,rectangular dissipation wells become a viable option.In response to the fact that release structures are usually arranged along the slope of the ground surface,numeri-cal simulation is used to study the effect of different jet angles on the hydraulic characteristics of rectangular dissipation wells under a specific flow rate.The results show that when the bottom slope of the spillway is not larger than 1∶6.5(θ≤8.75°),the jet in the dissipation well appears obvious upward deflection(ejection)phenomenon,and it cannot form a submerged jet;The flow velocity attenuation of only 44.5%,the vorticity is mainly concentrated in the surface of the water flow,and the turbulence in the dissipation well is not strong;When the bottom slope of the spillway is between 1∶6.5 and 1∶2.5(8.75°＜θ≤21.8°),the jet hardly deflects,the flow velocity decay in the process range rises and then decreases(68.9→79.6→69.6%),vorticity is able to diffuse throughout the dissipation well,and the range of turbulence induced by the jet increases and then decreases;When the bottom slope of the spillway increases above 1∶2.5(21.80°＜θ≤45°),the jet is obvious downward deflection,flow velocity attenuation with the shortening of the process to further reduces(69.6%-49.7%),vorticity distribution in the upper and lower sides of the jet,and water turbulence is mainly concentrated in the vicinity of the jet.Under submerged jet conditions,the well depth can be reasonably selected for dif-ferent incident angles so that the kinetic energy of the incident water body can be attenuated to the greatest extent within the process range.
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