| Unsteady flow is usually also called as hydraulic transients flow, which is an flow process varied with time。Flow changing and hydraulic accident is the common causation lead to unsteady flow. In water diversion project,unsteady flow usually occurs under condition of flow changing, such as hydraulic pressure,water depth, discharge,velocity,and so on.Because unsteady flow is not adopted in the design criterion,although it is critical with the safety of project,thus it became a common issue argued and discussed by designer and operator. In recent years, In view of the status of research in water diversion project,this thesis present theory of unsteady flow and devote effort to the studies on unsteady flow of water diversion projects.Studies have been made on some practical water diversion projects, Water from South to North in China. There are two common methods to study transient behavior in water diversion project, experimentation on hydraulic model and numerical simulation.It is difficult to make a whole integrated model for a long-distance water diversion project,the metamorphic model can not achieve a accurate simulation,numerical simulation is a proper choice for study unsteady flow,although it has deficient to simulate individual structure in detail.In order to get a better result,the thesis had studied unsteady flow of water diversion project by numerical simulation, through analysis for changes resulted in the hydraulic calculations, reasonable control scheme can be presented,which may be as the reference for engineering design. The main contents include three parts.(1) According to the basic theory of transient flow by setting boundary conditions, under the condition of transient flow mathematical model. Numerical simulation can be achieved.(2) Complete the numerical simulation of transient flow by mathematical mode(3) Based on the results of the analysis for the results of computation, recommendations canbe given for scientific decision-making. |
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