Numerical Simulation Study On Hydraulic Characteristics In Long Distance Water Diversion Tunnels

Water diversion is the most important and effective fashion in resolving water resource distributing uneven in space-time. At present, a lot of long distance interbasin water transfers have already been built in the world. As the variety of the topographical and geological condition of the long distance water transfer project, plusting the restriction of economy and technology factors, sometimes single pressure pipe or open channel isn't adopted. It often chooses the associative format of open channel and pipe As The formats of water diversion are becoming more and more complex, thus studies of hydraulic characteristics are becoming more and more important.On the basis of consulting a great deal of documents internal and external, and summarizing existing achievements, applying basic theoretics of unsteady flow and turbulent, corresponding calculating model with one practical project is established in the thesis, and analyses hydraulic characteristics of long distance water diversion tunnels are analysed.(1) In the thesis 1D mathematical model resolving the combination of water diversion format.for open channel flow and pressure flow is established The calculating equations are Saint-Venant equations. Pressure flow is sloved by the slot method. The positions of pressure flow transforming to free flow and the uniform flow depth of open channel.are studied Water surface profile of the whole tunnel and the sensitivity of roughness are also analysed.(2) Based on the k ?εmodel for turbulent flow, 3D mathematical model resolving transient process of pressure flow transforming to free flow is established in the thesis. The positions of pressure flow becoming free flow,water flow pattern and the uniform flow water depth of open channel are also studied.(3) The associative method of 1D and 3D mathematical model to analyse hydraulic characteristics of one practical long distance water diversion tunnels is adoped in the thesis That the results of 1D numerical simulation provide boundary conditions for 3D mathematical simulation, and the results of 3D numerical simulation of transition flow provide boundary conditions for 1D numerical simulation of pressure flow and open channel flow. This numerical model is proved reasonable by analysis and experimentations.