Research On Hydraulic Characteristics Of Shallow Submerged Jets At Depression Angles

Our country is rich in hydropower resources,at the top of the world.In the hydropower projects of southwest reign where dam construction in these ares mostly on mountain rivers,with head high,large flow,narrow valleys and other features,flood discharge energy dissipation are often the controlling factors of the entire water conservancy hub project.Due to the various energy dissipation work have their own disadvantages,how to efficiently solve the problem that energy dissipation and erosion control in the hydropower projects of southwest reign where dam construction in these ares mostly on mountain rivers,with head high,large flow,narrow valleys and other features is the key of the current research.In this paper,on the basis of predecessors’s research results,a new form of horizontal submerged jets energy dissipation has been porposed and the energy dissipation mechanism and hydraulic characteristics,pressure and velocity in the slab,the dissipation and its influencing factors and change law were analyzed and studied using theoretical analysis,physical model experiment and numerical simulation method of combination.The main findings and conclusions are as follows:(1)Connecting to the need of certain engineering,a new form of energy dissipation,named Near-surface Submerged Jet With Depression Angle,which based on the energy dissipation mechanism of the bottom of the traditional water jump and submerged jets.(2)Calculation formulas of conjugate depth and energy dissipation were obtained through theory analysis of submerged hydraulic jump in water cushion.(3)The influence of different angle of depression,the size of flow and the depth of downstream water pond on submerged submerged jet energy dissipator are analyzed.(4)The results of model test and numerical simulation inosculate preferably,which prove that numerical simulation is effective.(5)In the case of a certain angle,the maximum velocity of the bottom line center line and the maximum velocity of the vertical flow in the backflow of the bottom plate are changed with the flow rate,and the maximum center of the centerline of the bottom plate is deduced Flow rate and flow rate,and the relationship between the maximum flow velocity and the flow rate in the surface return.(6)The peak value of the pulsation intensity appears at the edge of the jet mainstream,and the impulse zone where the stagnation point is located is the region with the largest pulsation intensity.The velocity of the region is very unstable and the turbulence is strong.With the increase of flow in the water cushion pond along with the whole pulse intensity distribution of small changes,but the increase with each point pulse strength.(7)When free discharge happens in the water cushion pond near the upstream position fluctuation is bigger than the strength of submerged jets happens.In addition,in the different depth of the water cushion pond is down in the swimming pool at pulse intensity distribution changed little.