Experimental Study On The Law Of Gas Migration And Diffusion Of Aerated Water Flow In Bends

Natural rivers and water conservancy structures in nature often exist in a curved shape,and the water flow shows special hydraulic characteristics under the action of curves: horizontal deflection,curved circulation,and hydraulic flow axis offset These hydraulic characteristics affect the river's sediment movement,river navigation,and ecological environment.On the other hand,the aerated water stream formed by flood discharge and energy dissipation has different water aeration concentration distributions under different water flow structures,thus affecting the water ecological environment.In previous studies,the flow of the curve was more from the aspects of its flow structure,turbulent characteristics,and contaminant transport.The study of aerated water flow was more from the aeration mechanism and spillway and energy dissipator.Safety aspects.The effects of aerated redistribution on the buildings and water ecology under the effects of different water flow structures are neglected.Therefore,the experimental study on the migration and diffusion of aerated water under the special flow structure of curved channel is carried out.In this paper,the hydraulic model test combined with the theoretical analysis method is adopted.The energy-absorbing water body is an aerated water stream.The downstream section of the energy dissipator is arranged from the initial straight section,the leftward curve,the middle straight section,the right-hand curve,and the last straight section.The formed curve model analyzes the hydraulic characteristics of the water flow in the curve,and through the measurement of the concentration distribution of the aerated curve in the curve,it analyzes the effect of the flow structure of the curve on the distribution law of the aeration concentration and the diffusion and diffusion rate of gas in the curve.It can be concluded that the measured water level at the curve of the curve of the measured waterway begins to increase from the moment the water enters the curve,and increases to the maximum near the top of the curve.The ratio of the top of the curve to the exit of the curve decreases,after the exit.In the straight section,there is still a certain value of the horizontal ratio drop;the dynamic water pressure in the curve changes with the change of the water surface,the water surface of the concave bank increases after the water enters the curve,and the dynamic water pressure increases at the same time;The water surface of the concave bank decreases,the surface of the convex bank rises,and the mean water pressure decreases at the concave bank.The axis of the water flow force deflects from the centerline toward the convex bank as the water enters the curve.After the bend,the water flow force axis is toward the central axis to the concave.In the transition of the bank,the middle straight section is still close to the side of the concave bank after the exit;according to the distribution of the vertical velocity of the flow in the curve,the circulation flow from the entrance of the curve to the top of the curve is developed.The intensity of the circulation flow is greatest;The decreasing rate is different.The rate of change is different at different positions in the curve.Due to the influence of the circulation and flow axis,the change rate of the concentration of aeration in the convex bank first increases and then decreases in the curve,and the concave bank is reversed and is fitted according to the variation law along the course.Curve The calculation formula of the aeration concentration distribution rule of the concave-convex bank and central axis is calculated;the aeration concentration distributes approximately exponentially on the vertical line,and the distribution of the different banks is uniform;the horizontal aeration concentration distribution is longitudinally shown between two reversed curves Cycle distribution.The purpose of this paper is to enrich the study of flow characteristics and flow structure of curves and to study the variation of aeration concentration under different flow structures.