One Dimensional Long Distance Water Diversion System Of Hydraulic Research

The water resources in south are more than north in China, and the distribution is uneven with the land resources and economic development. The problem of supply and demand is outstanding. The effective mean is to build a long-distance and inter-basin water diversion project, to solve the unbalance between different regions and to achieve optimization. During the water transfer operation, the unsteady flow phenomena will happen, which is introduced by the change of discharge or the misuse of gate valves. And the unsteady flow will lead the water head and velocity change violently, which should be caused widespread concern in the relevant departments.For long-distance water diversion project exists open-full flow alternately, based on the Saint-Venant equations, using Preissmann slit hypothesis, a model for one-dimensional unsteady flow coupling free surface and pressure flow is developed to simulate the flow of network. And a pressure pipe network model for water hammer is built to simulate a sharp change such as water level process caused by the accident condition.Comparing the existing one-dimensional unsteady flow numerical solution method, taking into account the structural characteristics of the pipe network system itself, and this paper uses the staggered grid of discrete semi-implicit method for unsteady flow model. Using a first order upwind scheme makes convection term of motion equation is discrete, and the stability of the model increases. The water hammer equation, using the center differential implicit Crank-Nicolson scheme, has a second order accuracy and is unconditionally stable.The model is demonstrated on examples including steady pressure pipe flow, unsteady river net, and water hammer... By comparing the result of simulation with measured data in flood, the ability which model to solve complex shape of cross section is tested.Finally, the model is applied to Beijing South to North Water Diversion, analyzes the flow rate and water head distribution by different flow conditions and accident conditions, and provides the basis for relevant departments of the operation.